OF THE TONGUES OP THE MAMMALIA. 



641 



Balcenoptera horecdis (29). In the majority of the Odontoceti it 

 has the usual mammalian form, but it is slipper-shaped in 

 Grampus griseus and Lagenorhynchus alhirostris. 



The apex varies considerably. It is full and rounded in 

 Balcena and Balcenoptera. In the Odontoceti, on the other hand, 

 it Is not so full and rounded, and it may or may not have pro- 

 cesses and warty growths. In Glohicej^halus melas (25), Gephalo- 

 rhynclius eutropia (text-fig. 25 B), and Physeter macrocephalus 

 (text-fig. 25 A) it is plain and poiirted. In Grampus griseus 



Text-figure 25. 



Tongues of the Cetacea. A : dorsum of tlie tongue of a foetus of Thysetev macro- 

 cephahis ; B : lateral view of the same, showing the loose wrinkled frenum ; 

 C : tongue of Ceplialorhynclius eutropia, 



(text-fig. 26 A), Lagenorhynchus alhirostris (text-fig. 26 B), and 

 Delphinus delphis (text-fig. 26 C) it is broader and smooth, but 

 Cams and Otto (8) described and figured it as covered with 

 tubercles in the latter. The apical lobules are small in Phoccena 

 communis (text-fig. 27 A), large in Deljyhinapterits leucas (text- 

 fig. 27 B), and in two rows in Tursiops tursio (text-fig. 27 C). 



The latej-al borders are immense and massive in Balctnoptera 

 hoops, and thin in the fo3tal B. borealis. They are very variable 

 in the Odontoceti. In no Cetacean have they any lateral organs. 



