378 CETACEA. 



milk is expressed into the mouth of the animal by a 

 muscular action of the mammary organs, but there does 

 not seem to be any evidence in support of the theory. 

 The mother shows the greatest affection for her offspring, 

 as will be shown in several instances in our account of 

 the species, and constantly refuses to leave it if it falls 

 a victim to the harpoon of the whaler. 



The order Cetacea naturally divides itself into two very 

 distinct groups, which are regarded by our friend Prof. 

 Flower as deserving the rank of sub-orders, under the 

 names of Mystacoceti, bearded or " Whale-bone " Whales, 

 and Odontoceti, or toothed Whales. These differ in many 

 very important points of structure, of which we can only 

 point out a few of the more obvious, referring our readers 

 for more minute particulars to that gentleman's memoir 

 " On Irda and Pontoporia" in the Zoological Society's 

 " Transactions " for 1867. 



The most striking peculiarity of the Mystacoceti is the 

 absence of teeth, which are replaced by great plates of a 

 homy fibrous nature, which depend from the palate, and 

 constitute the baleen — the "Whale-bone" of commerce. 

 During fcetal life true teeth do exist, as was long ago 

 shown by Eschricht, but they are never developed, and 

 soon become absorbed. The baleen plates are smooth 

 on the external edge, but are frayed out, as it were, on 

 the inner side into a loose fringe. They spring from 

 transverse ridges on the side of the palate, and blood- 

 vessels pass into the cavities of their substance. The 

 whole structure of the skull is wonderfully modified in 

 connection with this peculiarity. It is of enormous size, 

 and is not laterally distorted, but the narrow rostrum 

 formed of the elongated maxillary and premaxillary bones 

 is greatly arched, while the branches of the lower jaw are 

 much bent outwards, and are only united in front by 



