18 



WHALES AND DOLPHINS. 



chiefly in the cold Polar seas, we cannot say 

 that they are wholly excluded from the 

 temperate and warm parts of the ocean. 

 The Basques formerly fished the Greenland 

 whale off their own coasts, and till about 

 1860 there was a whale-fishing station in the 

 channel separating the island of Trinidad 

 from the coast of South America. Only a 

 few individuals, to be sure, were captured 

 every year, but there were always some 

 caught sooner or later in passing through 

 this strait. We can thus assign a restricted 

 domain only to certain species, such as the 

 fresh-water dolphins, the beluga, the narwhal, 

 and the true porpoises, which are confined to 

 the northern seas; but as regards all the 

 other more or less abundant types, we must 

 say that they are found in all seas, and that 

 their presence in large numbers in this or that 

 sea appears rather to depend on secondary 

 causes, such as abundance of food, safety 

 from pursuit, and so forth. 



Similar difficulties are presented in in- 

 vestigating the origin of the cetaceans. In 

 the Cambridge Museum there are preserved 

 a few fossil vertebrae belonging to a whale 

 different from all other known species. They 

 were discovered in the diluvial loam of the 

 neighbourhood, but Professor, now Sir 

 Richard, Owen found the appearance of these 

 vertebrae to agree so closely with that pre- 

 sented by the fossil remains of the Kimmeridge 

 Clay of the locality, that he came to the 

 conclusion, a conclusion, however, only very 

 doubtfully expressed, that these vertebrae 

 may have been washed out of Jurassic strata 

 into the diluvial loam in which they were 

 found. If this surmise should be confirmed, 

 then these vertebrae would be the oldest 

 known remains of placental mammals, and 

 the cetaceans would, therefore, have to be 

 regarded as having preceded all other Mono- 

 delphia. ' In that case, accordingly, one 

 might not find the roots of this stock in other 

 orders from which it has been attempted to 

 derive it. This is still an open question. 



But with the exception of this still doubtful 

 case the earliest fossil remains of cetaceans 

 that have yet been found belong to the 

 Miocene. Europe has yielded a great num- 

 ber of such remains from Pliocene strata. 

 In the Pliocene period the mouth of the 

 Scheldt appears to have formed a bay in 

 which numerous shoals of whales were 

 stranded from time to time. America has 

 likewise yielded many of the same kind of 

 remains dating from Miocene times. But 

 these remains teach us nothing whatever 

 concerning the derivation of this order, for 

 the large groups of the toothed whales and 

 whalebone whales are already represented in 

 the Miocene, and even the secondary sub- 

 divisions are not wanting there. It may 

 accordingly be said that from a palaeontological 

 point of view the Cetacea present themselves 

 on their first appearance with all the characters 

 which now distinguish the various groups. 



Embryological studies, again, are too in- 

 complete and fragmentary to allow of any 

 well-grounded conclusions on this matter. 

 Anatomy reveals to us a number of points 

 which indicate a low organization related to 

 that of the reptiles. The absence of marrow 

 cavities in the long bones; the spongy nature 

 of the bony tissue generally; the structure of 

 their vertebrae, only imperfectly fused with 

 their apophyses ; the arrangement of the bones 

 of the skull, which often exhibits gaps and 

 breaches of continuity ; the uniform character 

 of the dentition, which is composed of un- 

 specialized teeth often set in a continuous 

 groove without distinct sockets, the absence 

 of fleshy movable lips, the smallness of the 

 brain compared with the size of the body- 

 all these characters appear to be derived from 

 the reptiles. The fore-limbs, although re- 

 maining in a certain measure in the embryonic 

 condition, yet show by their organization, 

 and especially by the large number of the 

 phalanges, or small bones of the fingers, a 

 tolerably close resemblance to those of the 

 large extinct sea-reptiles, the Enaliosaurii, 



