123 



CHAPTEE XVII. 



CAENIVORA continued SEALS — EXTINCT SPECIES EXISTING SPECIES SEALS IN CASPIAN SEA 



AND LAKE BAIKAL — WALRUS. 



Phocid.e. — Seals. (Map 28.) The origin of marine mammals by descent, in other words their 

 derivation or parentage, has always appeared to me one of the most difficidt problems to solve. How 

 a terrestrial animal could ever give birth to a Seal or a ^Vliale, — how it could ever nurse it or feed it, 

 naturally makes us pause and wonder. The very first and most essential qualification, of a common 

 medium in which to live, seems wanting. The solution undoubtedly is to be arrived at through those 

 terrestrial animals which are amphibious. When. we come, however, to think of the steps and processes 

 by which this creation may have been effected we find ourselves wholly at sea without compass or 

 rudder. We do not even know at which end to commence our speculation. Were the aquatic 

 animals descended from the terrestrial or the terrestrial from the aquatic ? Although the probabilities 

 seem in favour of the former, there is no fact known which wholly shuts out the possibility of the 

 Seals having been in existence before the other carnivora. If they really were so, we might have to 

 reverse the most natural theory, and make them the parents, instead of the descendants, of the 

 land carnivora. The latter is the more natural theory, because it seems to stand to reason that 

 the exceptional form shoiild be derived from the nonnal rather than the reverse ; although if 

 pressed for a reason why one should bo considered more normal than the other, I must candidly 

 confess that I have none to give, except the very lame one that now the one is more numerous in 

 species than the other. 



I scarcely think it necessary to discuss the possibility of the Seals being allied to the Whales, 

 although they are placed by many authors together.* Their plan of structure seems too decidedly 

 distinct to allow us to regard them as belonging to the same stock. 



The first thing to guide us to a true understanding of the matter is to ascertain when the 

 particidar aquatic mammals inquired after first appeared on the face of the globe. If before other 

 mammals related to them, the probabilit)' would be increased that they were the progenitors of their 

 relations on dry land. But in the Seals we have not sufficient information to enable us to start 

 even from this point. In the secondary formations mammals appear to have been merely starting 

 into life ; a few small marsupials in the Purbeck beds and trias being all that are known. And 

 in the immense chalk dejjosits which succeeded these formations it is usually said that no mammalian 

 remains have ever been found, and it is not easy to see how any remains of terrestrial mammals ever 

 could have been found. These formations arc all marine deposits, not even estuaries, but beds 

 deposited out at sea in blue water. It would surely be a most extraordinary chance by which a 

 terrestrial animal should be preserved in such circumstances ; and a stiU more extraordinary chance 

 that shoidd allow us to lay our fingers upon such a waif. Seals, "Whales, and Sirenia, are the onlj' 

 mammals whose remains we might (if these animals were in being at that epoch) reasonably exjjcot 

 to find traces of ; and curiously enough the two former are tlie only two, remains of whicli have been 

 ascribed to the secondary formations. A vertebra of a Doljihin and a tootli of a Seal are re- 



* GiEiiEL, " Die Saugcthicre," &c. See Sy.stenis of Classificatiou in the Appciulix, No. I. 



