I also collect books on dinosaurs. Not only do I collect them, but I'm also creating a "List of Japanese Dinosaur Books," which aims to document every dinosaur book ever published in Japan (even if it just mentions a dinosaur briefly, or even just on the cover, I count it as a "dinosaur book"). The list, which I started in a college notebook in the early 90s, currently numbers 3,772 books as of May 2012 (I own a little over half of them?). And since it will continue to grow until all books are replaced by e-books or Japan ceases to exist, it's a lifelong endeavor that I can't quit until I die (hopefully, someone will take it over).

When that list is arranged chronologically, the fifth item to appear is "Textbook of Paleontology" (化石学教科書) by Dr. Mataro Yokoyama, published in 1894 (Meiji 27).

In 1992, in the Dinosaur Club's newsletter "DINO," the question arose: when and by whom was the word "Dinosaur," coined by Richard Owen in 1842, translated as "恐竜 (kyouryuu)" (meaning "fearful dragon")? It was decided that "恐龍類 (kyōryū-rui)" (Dinosauria), noted in the aforementioned "Textbook of Paleontology," was likely the first. I even went to the National Diet Library, copied the dinosaur-related pages from the "Textbook of Paleontology" on microfilm, and proudly presented them in the newsletter.
In 1994, in issue 6 of the legendary dinosaur specialized magazine "Frontiers of Dinosaur Studies," Megumi Ito, a "bone scholar," wrote a similar, more detailed article titled "The Beginning of Dinosaur Studies."

Twenty years have passed since then. Thanks to the internet, "Textbook of Paleontology," which could only be viewed on microfilm at the National Diet Library, and many other dinosaur-related works by Dr. Mataro Yokoyama are now on my bookshelf. What's even more surprising is that I can freely view and copy the contents of these valuable books online, without having to spend time and money copying microfilm at the National Diet Library. What a changed world it is.

Now, I'm going to boast about my Mataro Yokoyama collection, along with URLs to their content and the "page" (not the actual page number, but the □/total pages displayed on screen) where dinosaurs appear. But before that, let's look at the face of Mataro Yokoyama, the founder of Japanese dinosaur studies.
Mataro Yokoyama (from "Fuzanbo Gojunen")
For his profile, please see here:
https://kotobank.jp/word/%E6%A8%AA%E5%B1%B1%E5%8F%88%E6%AC%A1%E9%83%8E-146087 https://www.weblio.jp/content/%E6%A8%AA%E5%B1%B1%E5%8F%88%E6%AC%A1%E9%83%8E

Photo 1: "Textbook of Paleontology, Middle Volume" (1894)
*I trembled when I found this on an online used bookstore site. (And it was surprisingly cheap!)
http://kindai.ndl.go.jp/info:ndljp/pid/831231　　94/145

Photo 2: "Previous World" (1898)
http://kindai.ndl.go.jp/info:ndljp/pid/831264　　36/53

Photo 3: "Past and Future of Living Things" (1902)
http://kindai.ndl.go.jp/info:ndljp/pid/901959　　 6/32

Photo 4: "Paleontology" (1907)
*This is a revised edition that combines the three volumes of "Textbook of Paleontology" into one.
http://kindai.ndl.go.jp/info:ndljp/pid/901867　　 176/299

Photo 5: "Prehistoric World History" (1918)
http://kindai.ndl.go.jp/info:ndljp/pid/956582　　 209/356

Photo 6: "Outline of Paleontology" (1920)
http://kindai.ndl.go.jp/info:ndljp/pid/960386　　 248/418

Items 1 to 4 on the "Dinosaur Book List" are dinosaur books from before the word "dinosaur" was coined. Unfortunately, I haven't acquired anything except for the third item, but I was able to get information from the "Frontiers of Dinosaur Studies" article and online.

"The Origin of Species" (1879)
By Thomas H. Huxley, translated by Shuji Izawa
This book is not available for online viewing, but according to Mr. Ito of "Frontiers," Pterodactyls, Ichthyosaurs, and Plesiosaurs are introduced with illustrations (available in the complete edition mentioned later). This would mean that the translator rendered "saur" as "snake"... but that doesn't apply to pterodactyls.

"Theory of Animal Evolution" (1883)
Recited by Edward S. Morse, recorded by Chiyomatsu Ishikawa
There is no translated word.
http://kindai.ndl.go.jp/info:ndljp/pid/832826/5
Dinosaurs (along with Mastodons, Pterodactyls, Ammonites) 22/87
Dinosaurs 79/87
When I tried searching for it on a used bookstore site, I found one copy, and guess what! It was 157,500 yen!

Photo 7: "Hakuan Kyoki: Journey to the Center of the Earth" (1885)
This is the first translated edition of Jules Verne's "Journey to the Center of the Earth." This is also a book I once saw on microfilm at the National Diet Library. I found it online and impulsively bought it for over 40,000 yen.
http://kindai.ndl.go.jp/info:ndljp/pid/897051
In the tenth chapter of the main story, there is the famous confrontation scene between a Plesiosaurus and an Ichthyosaurus. 55/144
Illustrations from the original book are used throughout, but they are mostly blacked out and barely visible online, so I will omit their introduction. The same illustrations can be seen in the Iwanami Bunko edition, etc.
The latter half of the book is a science reading titled "The Birth and History of the Earth." 91/144
In addition to the Plesiosaurus and Ichthyosaurus that appeared in the main story, Geosaurus and Pterodactyl are introduced, and among dinosaurs, Megalosaurus and Iguanodon are introduced, but of course, the word "dinosaur" is not present. 129/144

"Principles of Evolution" (1889)
This is the complete translation of the aforementioned "The Origin of Species." It can be viewed online. Illustrations are here. 　41/151

Another theme of "Frontiers of Dinosaur Studies: The Beginning of Dinosaur Studies" was whether there were any other Japanese translations for "Dinosaur" besides "Kyōryū" at the time. Ito wrote that there seemed to have been a translation "恐蜴 (kyōeki?)," but the source could not be confirmed. And here is that source. (As I write this, I can't help but look smug)

Photo 8: "Outline of Zoology" (1918)
This is a splendid, boxed book with 950 pages and abundant illustrations. Kyōeki is here. 445/506　

Furthermore, in the Showa era, there was also the translation "恐蜥 (kyōseki?)."
"The Origin and End of the World and Living Things" by Shigeomi Ishii (Hakuyosha, 1932)
Since it's not online, I'll introduce a short excerpt from the original text.
"This kangaroo-like reptile belongs to the famous category of Kyōseki (Dinosauria)—"

Please enjoy this moving, almost time-traveling, feature on dinosaur books from the Meiji and Taisho eras. It's an article from the April 1924 issue of "Science Knowledge."
It's a report on the achievements of the Andrews expedition, which took place "the previous year."

Photo 9: Cover

Photo 10: Article