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Isthmus of Tehuantepec, southern Mexico. This last one 1 saw 

 from the deck of a steamer, and I remember very well that it was 

 in shallow water, and that it had drawn itself partly out on the 

 muddy ooze of the bank, so that its form was very fairly exposed 

 to my view. 



Nevertheless 1 am quite familiar with this Order of Mammals, 

 and it will be my aim here to review some of the more important 

 parts of the history of them so far as it is at present known to 

 naturalists. 



Geology goes to show that the early Pliocene and Miocene seas 

 of Europe swarmed with several species of animals, which zo- 

 ologists have good reason to believe were the latter extinct an- 

 cestors of existing Sirenians (Ralitherium). But the intermedi- 

 ate forms which connected our living types, such as the Manatee, 

 with the ancient ones, to which I refer, have not as yet been dis- 

 covered. Zoologists have also held, and I think it is very proba- 

 ble too, that the Manatees and their kind are in some way related 

 links, remotely affined to the Cetaceans on the one hand, and the 

 Ungulata on the other; but even of this kinship the evidence is 

 as yet not satisfactorily demonstrated. Various other extinct 

 sirenian species have received different names at the hands of 

 paleontologists, but it is not our object to further pursue this part 

 of the subject here; one form, however, recently exterminated, 

 fully deserves a. word of passing notice, and I have reference of 

 course to the Northern Sea-cow (Rhytina stelleri). 



Of it. Professor Flower has said, " Only one species of this 

 genus is known. A', stelleri, the Northern Sea-cow, by far the 

 largest animal of the order, attaining the length of 20 to 25 ft. It 

 was formerly an inhabitant of the shores of two small islands in 

 the North Pacific, Behring's and the adjacent Copper Island, on 

 the former of which it was discovered by the ill-fated navigator 

 whose name the island bears, when, with his accomplished com- 

 panion, the German naturalist, Steller, he was wrecked upon it 

 in 1741. Twenty-seven years afterward (1768), as is commonly 

 supposed, the last of the race was killed, and its very existence 

 would have been unknown to science but for the interesting ac- 

 count of its anatomy and habits left by Steller, and the few more 

 or less perfect skeletons which have recently rewarded the re- 

 searches carried on in the frozen soil of the islands around 

 which it dwelt. There is no evidence at present of its having in- 

 habited any other coasts than those of the islands just named, 



