191-1] Taylor: Aquatic Adaptation in the Carnivora 473 



The facts of relationship seem to the writer to be somewhat 

 more adequately shown by the former course, and consequently 

 the sea-otter is here referred to the Lutrinae. 



Nature op the Characters Separating Latax and Lutra 



Although, as previously suggested, a superficial examination 

 of the skeleton of Latax reveals no very emphatic modifications 

 in the form of the bones, except in the hind foot, such as might 

 be expected to occur in response to an aquatic environment, a 

 closer scrutiny brings to light the fact that adaptations of this 

 nature affect almost every bone in the body, and indicates that, 

 outside the Pinnipedia, Latax is the most highly specialized for 

 life in the water of all the carnivores. 



Reference to the following table shows further that many of 

 the characters distinguishing Latax lutris nereis from Lutra 

 canadensis may be ascribed to the effect of natatory modification. 



DIFFERENTIAL CHARACTERS, OSTEOLOGICAL AND DENTAL, 

 APPARENTLY RELATED TO AQUATIC ADAPTATION 



Lutra canadensis 



1 Skull relatively not enlarged 



in proportion to length of 

 trunk. 



2 Brain-case relatively not in- 



flated. 



3. Orbit small relative to length 

 of skull. 



4 Lambdoidal ridge and sagittal 



crest little developed. 



5 Anterior ends of nasals a short 



distance posterior of an- 

 terior ends of premaxil- 

 laries. 



6 Interorbital constriction nar- 



row. 



7 Tooth formula 



8 Cheek-teeth with a cutting 



function. 



9 Lower carnassial with para- 



conid large. 



Latax lutris nereis 



1 Skull heavy, massive, rela- 



tively much enlarged in 

 proportion to length of 

 trunk. 



2 Brain-case inflated. 



3 Orbit large relative to length 



of skull. 



4 Lambdoidal ridge and sagit- 



tal crest highly developed. 



5 Anterior ends of nasals al- 



most directly above anter- 

 ior ends of premaxillaries. 



6. Interorbital constriction broad. 



7 Tooth formula 



_ « i . — < i V 9, — 39 

 2 13 2 — 



8 Cheek-teeth with a crushing 



function. 



9 Lower carnassial with para- 



conid much reduced. 



