That was a very good idea with the 1911 EB!

Does this fit the bill? From 1861, free Google ebook.

Biologist here, although no expert in fossil fish. My bet, anyway, is that you won't find any book mentioning "the coelacanth" as an extinct species.

What we think instinctively today when we hear the word "coelacanth" is the modern South African species discovered in 1938, Latimeria chalumnae (there is another that was later discovered in Indonesia, L. menadoensis). L. chalumnae was not described from fossils (in fact, I'm not even sure if fossils of L. chalumnae have ever been found), but from recent specimens in African fish markets. So people couldn't describe "the", "our" coelacanth, L. chalumnae as an extinct species in publications before 1938, because there was no clue that L. chalumnae existed or had ever existed before that date, when it was discovered alive and not as a fossil!

(This is not the case of other animal species: the Mountain Tapir Tapirus pinchaque and the Balearic Midwife Toad Alytes muletensis, for example, were both originally described from fossils, and living animals of these species were only discovered after).

So, why do people say that the coelacanth, meaning L. chalumnae, is a "living fossil" (words that some biologists and paleontologists don't like and consider misleading, by the way)? It is because the group of species where L. chalumnae is included in, collectively called coelacanths or coelacanthids (Subclass Actinistia, Order Coelacanthiformes, Family Coelacanthidae), was discovered and defined from fossil species different to L. chalumnae, years before L. chalumnae itself was discovered. The fossil coelacanths are a group way more varied than they are commonly credited to be. During the Mesozoic era there were marine and freshwater species, species of shallow and deep water, and both slow swimming species (like modern coelacanths) but also more stylized, fast swimming coelacanths. To paleontologists of 1938 and earlier, this whole group of the coelacanths seemed to go extinct at the end of the Cretaceous, because there had not been any fossils found of any species of coelacanths in post-Cretaceous sediments at that point. Since 1938 we have found both the two living species, and also other fossil species of Cenozoic age, one in Israel if I remember correctly.

As an example, imagine that there were no birds on Earth. One day, a paleontologist finds a fossil of Archaeopteryx and describes it as a new fossil species. Then another finds Icthyornis. Then another finds Hesperornis. Then another Iberomesornis. After examining them, it is decided that all four of them are different species, but that they are more related to each other than they are to any other animal, living or extinct. A new group, a clade called Aves, is created to include all four of them and only them, and defined as the animals possessing characteristics that all four species have in common but no other animal has, like three fingered wings and feathers. All four species are older than the end of the Cretaceous, and since the end of the Cretaceous is marked by a massive change in fossil faunas, Aves are counted as one of the fossil groups that went extinct in that time. But then, someone finds a sparrow in a Chinese market, examines it, describes it, and names a new species part of the clade Aves: Passer domesticus.

Would you say that the sparrow is a "living fossil"? You have actually not found any fossils sparrows. You have no evidence that the sparrow as a species or even as a genus existed in Mesozoic times, but you know that the sparrow is a bird, a member of Aves, and that all other birds known are more than 66 million years old. You have proven that not all birds went extinct at the end of the Cretaceous, because you have a living bird today (or any bird more recent than the end of the Cretaceous), but you don't have a living Archaeopteryx or a living Iberomesornis. You have a living sparrow, P. domesticus, that might descend from any of them, or from some other Mesozoic bird still unknown to Science. That's irrelevant.

So, did you make a groundbreaking discovery? Yes. Will any books before your discovery say that P. domesticus is an extinct species? No, because people had no idea of P. domesticus when those books were written and published. Those books would say that Aves in general, birds, is a group of Mesozoic fossil vertebrates. That's it.

So going back to coelacanths, at best, you might find old Paleontology books listing groups of extinct fish and including Coelacanthidae or Actinistia among them. But not a line saying "the coelacanth, i.e. Latimeria chalumnae, is an extinct species of fish".