While I was able to complete my collection of translated editions of "Journey to the Center of the Earth," "The Lost World" proved more challenging. Below is a chronological list of all the known editions, including those I don't yet own (marked with "(Unowned)"):

1924 "Kikai no Ashiato" by Utsuki Moto / Shineikaku (Unowned, no image)
1925 "Botsuraku no Sekai" by Shinto Shin / Kongosha (Unowned)
*Featured in Shin Hihokan Vol. 7. Can be read at "Kindai Digital Library": http://kindai.ndl.go.jp/info:ndljp/pid/919093
1929 "Zen Sekai Monogatari" by Oto Kiichiro / Kinransha (Unowned, no image) *Found in an online used bookstore, but 70,000 yen was too much...
1931 "Zen Sekai Tanken" by Oto Kiichiro / Kinransha (Unowned) - A new edition of the 1929 version.
1947 "Kyoryu no Ashioto" by Takagaki Hitomi / Kaiseisha
**Featured in Shin Hihokan Vol. 7.
1948 "Kaiju Koku Tanken" by Ban Daisaku / Meimeisha (Unowned)
1949 "Kyoryu no Ashioto" by Takagaki Hitomi / Kaiseisha (Unowned)
*A new edition of the 1947 version.
1954 "Ushinawareta Sekai" by Osaragi Jiro / Koyana Shoten
*Sekai Taishu Shosetsu Zenshu 1
1955 "Kyoryu no Ashioto" by Takagaki Hitomi / Kaiseisha
*A significantly expanded and revised edition of the 1947 version.
1955 "Ushinawareta Sekai" by Shioya Taro / Kodansha
1958 "Ushinawareta Sekai" by Karasawa Michitaka / Kin no Hoshi Sha (Unowned, no image) *Hiragana Sekai Meisaku
1960 "Kyoryu no Ashiato" by Katafusa Zenji / Iwasaki Shoten
1960 "Lost World" by Fukushima Masami / Gakken *Junior High First Year Course Appendix
1961 "Ushinawareta Sekai" by Nobuhara Ken / Shincho Bunko
1961 "Ushinawareta Sekai" by Shiraki Shigeru / Gakken
*Fifth Grade Study Appendix
1963 "Lost World" by Shinjo Tetsuo / Hayakawa SF Series
1965 "Kyoryu no Daichi" by Shioya Taro / Obunsha
*Second Year Middle School Era Appendix
1966 "Ushinawareta Sekai" by Shiraki Shigeru / Kaiseisha
*Meisaku Boken Zenshu
1967 "Ushinawareta Sekai" by Nagai Jun / Kadokawa Bunko
1967 "Kyoryu no Sekai" by Kume Minoru / Iwasaki Shoten
*SF Sekai no Meisaku
1968 "Ushinawareta Sekai" by Takagaki Hitomi / Kaiseisha
*Shonen Shojo Sekai no Meisaku - Same content as 1955 "Kyoryu no Ashioto"
1969 "Ushinawareta Sekai" by Kano Ichiro / Gakken *Fifth Grade Study Appendix
1969 "Ushinawareta Sekai" by Ryuguchi Naotaro / Sogen Suiri Bunko
1970 "Lost World" by Kajima Shozo / Hayakawa Shobo *Sekai SF Zenshu
1970 "Ushinawareta Sekai" by Doi Kou / Iwasaki Shoten
*SF Shonen Bunko
1971 "Ushinawareta Sekai" by Shirayanagi Yoshihiko / Poplar Publishing
*Sekai no Meicho
1971 "Kyoryu Sekai no Tanken" by Shiraki Shigeru / Akane Shobo
*Shonen Shojo Sekai SF Bungaku Zenshu
1972 "Kyoryu no Sekai" by Hikawa Ro / Poplar Publishing (Unowned)
1973 "Saigo no Kyoryu Sekai" by Nanzan Hiroshi / Asahi Sonorama (Unowned)
1973 "Kyoryu no Sekai" by Segawa Masao / Shueisha *Haha to Ko no Meisaku Bungaku
1974 "Ushinawareta Sekai" by Shiraki Shigeru / Kaiseisha (Unowned)
*Boken Tantei Series - Renovation of the 1966 edition
1974 "Kyoryu no Sekai Tanken" by Tezuka Osamu (ed.) / Gakken *Gekiga Suspense
1975 "Ushinawareta Sekai" by Shioya Taro / Tsuru Shobo
*Same translation as the 1955 Kodansha edition
1975 "Ikiteita Kyoryu" by Karasawa Michitaka / Kin no Hoshi Sha *Same as 1958 "Ushinawareta Sekai"
1976 "Kyoryu no Sekai" by Kume Minoru / Iwasaki Shoten (Unowned)
*SF Kodomo Toshokan - Same as the 1967 edition
1977 "Ushinawareta Sekai" by Sadamatsu Tadashi / Shun'yodo Shoten
*Shun'yodo Shonen Shojo Bunko
1978 "Ushinawareta Sekai" by Doi Kou / Iwasaki Shoten
*SF Shonen Bunko - New edition of the 1970 version
1979 "Kyoryu no Sekai" by Uchida Shigeru / Shueisha
*Kodomo no Tame no Sekai Meisaku Bungaku
1983 "Ushinawareta Sekai" by Yamau Toshihiko / Gyosei
*Shonen Shojo Sekai Meisaku Zenshu
1986 "Ushinawareta Sekai" by Doi Kou / Iwasaki Shoten (Unowned) *SF Roman Bunko - Same as the 1978 version
1994 "Ushinawareta Sekai" by Ryuguchi Naotaro / Sogen SF Bunko *New edition of the 1967 version
1994 "Kyoryu no Sekai" by Uchida Shigeru / Shueisha
*Kodomo no Tame no Sekai Bungaku no Mori - New edition of the 1979 version
1995 "Akuma no Sumu Daichi" by Takano Takako / Shogakukan
1996 "Ushinawareta Sekai" by Kato Shozo / Hayakawa Bunko SF *Same translation as 1970 "Sekai SF Zenshu"
1998 "Ushinawareta Sekai" by Mori Ei / Kodansha
*Tsukai Sekai no Boken Bungaku
2002 "Mori Ei no Ushinawareta Sekai" by Mori Ei / Kodansha
*Series Adventure - New revised edition of the 1998 version
2003 "Lost World" by Kume Minoru / Iwasaki Shoten
*Boken Fantasy Meisaku Sen
2004 "Ushinawareta Sekai" by Kan Hiroshi / Kodansha Aoi Tori Bunko
2009 "Ushinawareta Sekai" by Ryuguchi Naotaro / Sogen SF Bunko *Limited cover edition
2015 "Ushinawareta Sekai" by Kan Hiroshi / Kodansha Aoi Tori Bunko *New edition
2016 "Ushinawareta Sekai" by Fushimi Iban / Kobunsha Koten Shinyaku Bunko

Please enjoy the cover images.

(Image 1) Pre-war to 1960s

(Image 2) 1970s

(Image 3) 1980s to present

This time, I flipped through the books in my collection and compared the dinosaur appearance scenes, which was quite interesting. The ancient creatures mentioned by name in the original novel include Stegosaurus, Iguanodon, Allosaurus, Megalosaurus (there's a fascinating scene where two scientists, hesitant to classify the large theropod that attacked them as anything more than a type of carnivorous dinosaur, discuss whether it might be an Allosaurus or Megalosaurus, tickling the hearts of fans), Dimorphodon, mentioned only once by Professor Challenger, the very active Pterodactyl, Plesiosaurus and Ichthyosaurus, specifically noted as freshwater, and the minor character Toxodon. However, for some reason, Japanese names were often used in translated books until around the 1970s. (It's understandable for pre-war works, given the times.)
Pterosaur, Plesiosaur, Iguanodon (referred to as "bird-dinosaur" - 禽竜), and Allosaurus (referred to as "strange dinosaur" - 異竜) are fine, but Megalosaurus, whose official Japanese name is "spotted dragon" (斑竜), was often translated too literally as "giant dragon" (巨竜) by Osaragi Jiro in 1954, and this trend led to uninspired names like "large dinosaur" (大恐竜).
In the immediate post-war translation by Takagaki Hitomi, perhaps due to a lack of research, the furigana for "bird-dinosaur" (禽竜) was "Brontosaurus," and the carnivorous dinosaur that attacked it was simply called "dinosaur" with "Iguanodon" as furigana. Whether this was the origin of the confusion or not, the 1955 translation by Shioya Taro features an illustration of a Brontosaurus in the Iguanodon scene. Perhaps taking advantage of this, Shiraki Shigeru, in his three translations from the 60s and 70s, intentionally replaced Iguanodon with Brontosaurus and even introduced Tyrannosaurus (whose illustration, moreover, has horns and three-fingered hands!). Did the translators and illustrators not consult encyclopedias, but rather referenced earlier translations?

What was astonishing was the 1960 appendix to the magazine "Chuichi Course," translated by Fukushima Masami, a doyen of the SF world (though often ignorant about dinosaurs). The climax, where released pterosaurs fly around the reporting hall and then cross the ocean towards the Amazon, is completely cut out, replaced by a single sentence: "It goes without saying what a commotion the announcement at the conference caused." ...But I want you to say it!

A unique edition that reflects its era is the 1998 version, freely modified by Mori Ei. The dinosaur in the sketchbook is a Brachiosaurus. Other dinosaurs like Velociraptor, Acrocanthosaurus, and Anhanguera appear in droves, disregarding the original time setting. The natives reconcile with the ape-men, and in the end, to protect the Maple White Land, Professor Challenger himself admits the expedition's failure and reports that no dinosaurs were discovered.

Like "Journey to the Center of the Earth," "The Lost World" also has many juvenile editions.
Compared to "Journey to the Center of the Earth," where the lengthy journey to the crater is often abridged, "The Lost World" is adventurous from the start, so even in juvenile editions, many episodes from the original are preserved. However, there were a few books that omitted the initial incident with Ms. Gladys, which is what leads the protagonist to join the expedition (and has a punchline at the end).

Ultimately, the most complete and well-rounded edition with the fewest points to criticize is the Kobunsha "Koten Shinyaku Bunko" version published this year. It's also a treat to see the illustrations from when it was serialized in "Strand Magazine" in 1912.

I've gathered some nostalgic illustrations.

(Image 4) Pterodactyl nesting ground

(Image 5) Carnivorous dinosaur's night attack

(Image 6) Other scenes arranged in story order.

Gladys / Mabel White's sketchbook / Two Iguanodons / Stegosaurus by the lake / Carnivorous dinosaur attack on the tribe / Pterodactyl flying in the hall / Pterodactyl heading home

There are also several novels related to "The Lost World."

"Lost World 2" (Tanaka Koji / Tokuma Shoten / 1980) is a sequel where the same members go in search of the legendary Inca golden city of Manoa. A two-headed Tyrannosaurus worshipped as a god appears, but it's completely unsatisfying "dinosaur-wise."

"Jingai Makyo no Nazo" (Yokota Junya / Shincho Bunko / 1991) is also a sequel, but here a Japanese expedition aims for Mabel White Land. The setting is 1911 (Meiji 44). The German Imperial Army also appears, and many dinosaurs, particularly with carefully chosen "Japanese names," make an appearance. The introduction of major characters at the beginning includes a useful list of major dinosaur characters with both Japanese and English names. However, Megalosaurus is still "giant dragon" (巨竜).

"Iguanodon no Uta" (Nakaya Ukichiro / Bungeishunju Shinsha / 1952) is not a novel, but an essay included in a collection of the same name, recounting an episode from the end of the war, a night in an empty Hokkaido, where the author reads "The Lost World" to children. It's featured in "Kyoryu Bungaku Taizen" (edited by Higashi Masao / Kawade Bunko / 1998 - a must-have!) which compiles Japanese short dinosaur literature, and can also be read online: http://www.aozora.gr.jp/cards/001569/files/53201_49836.html

"Boy's Life - Part 2" (Robert R. McCammon / Bungeishunju / 1995) is a novel describing a year of bittersweet childhood in a rural American town in the 1960s, a blend of fantasy and reality. In a chapter titled "From The Lost World," the protagonist sees an animal resembling a Triceratops with a broken horn in a traveling carnival's sideshow. The ticket seller claims Professor Challenger brought it back from the Amazon plateau... (In Part 1, he also encounters a mysterious aquatic reptile, the master of the river.)

Although no dinosaurs appear, "Sherlock Holmes and the Beast Men of Moreau" (Guy Adams / Takeshobo Bunko / 2015) features three "dinosaur-related individuals": Professor Challenger before his expedition to the plateau, Professor Lidenbrock, who explored the center of the Earth 30 years prior but is now disregarded, and engineer Abner Perry, who later develops the iron mole drill and reaches Pellucidar with David Innes. Also present is Cavor, who invented the anti-gravity substance Cavorite and travels to the moon. However, apart from Professor Challenger, the others only appear briefly at the beginning, and Professor Challenger himself is disappointing, doing little more than kicking down a door. Holmes's adversaries are, of course, the legacy of the mad scientist of that isolated island, Dr. Moreau, and his beast-men.

Since this has become unexpectedly long, the planned "The Lost World - Movie Edition" will be next time.
I will also introduce the treasured goods I'm supposed to get at the "Hakubutsu Festival" in July.

Finally, please see this:
http://kogundou.exblog.jp/16206138/
This appears to be something created by a cinema when the movie "The Lost World" premiered before the war. A few years ago, I found it in an online used bookstore, hesitated for a moment at the 20,000 yen price, and then it was snatched away by another collector (probably of sugoroku games). It's a regretful item. The image from that time remains online. How I wish I had it now to boast about...