1885.] DR. ST. G. MIVART ON THE ARCTOIOEA. 387 



Aonyx^. — This small genus of the species from Nepal, Java, 

 Sumatra, and South Africa, differs from Lutra in its rudimentary or 

 even obsolete claws, and in having the feet only slightly webbed. 

 The palmar and plantar surfaces are quite naked, or at most have 

 but a few scattered hairs. 



There are 14 dorsal, 6 lumbar, 3 sacral, and 20 caudal vertebrae. 

 The ultimate phalanges of the manus and pes are much shorter 

 relatively than in any other Arctoid. The breadth of the brain-case, 

 compared with the length of the skull, is at its maximum amongst 

 Arctoids, as is the length of the first lower true molar. 



Caudal vertebrae with hypapophyses depending from the hinder 

 end of the centrum of the first and of the second vertebrae and from 

 the front end of the centrum of the third vertebra and of the suc- 

 ceeding vertebree to the tenth. Three real chevron bones are placed 

 beneath the intervals of the vertebrae, between the third and the 

 sixth. 



The humerus has a condyloid canal. The radius develops no 

 process from the ulna. The acromion is very slender. No special 

 ectotrochanteric ridge to femur. Ultimate phalanges exceedingly 

 minute ; those of pes slightly lower than those of manus. 



The skull resembles that of Lutra, save that it is less flattened, 

 especially the bullae. The cranial ridges are generally smaller, as 

 are the mastoid and paroccipital processes. The pterygoids tend 

 less to depend. There are no defects of ossification in the exocci- 

 pitals. 



Molar formula=P. ~, M. \. 



The true molars are more massive than in Lutra. The first 

 upper molar is large relatively and more preponderating over the 

 fourth premolar. 



Enhydra^. — This very peculiar genus, containing only a single 



1 Lesson, Mamm. p. 157; Fischer, Synop. p. 228; P. Gervais, Mamm. ii. 

 p. 118 ; Gray, P.Z. S. 1865, p. 129; id. Cat. Cai-niv. B. Mas. p. 109 ; Hoi-sfiekl, 

 Zool. Eesearch, yii. ; Eaffles, Linn. Trans, xiii. p. 254 ; De Blaiuville, Osteogr. 

 Miisiela. 



- Mustela Mris, Linn. Syst. Nat. i. (1758) p. 45, no. 1 ; Sclireber, Saug. iii. 



(1777) p. 128 ; Gmeliu, Syst. Nat. i. (1788) no. 1. 

 Musfela, De Blainville, Ost6ograpbie. 



Phoca lutris, Pallas, Zoog. Rosso-As. i. (1831) p. lUO, no. 34. 

 Lutra lutris, Gray, P. Z. S. 1865, p. 136, pi. vii. and Oat. Oarniv. B. Mus. 



p. 118. 

 Lutra nmrina, Steller, Nov. Ann. Petrop. ii. (1751) p. 367, tab. xvi.; Erxle- 



ben, Syst. Nat. (1777) p. 445 ; Schreber, Saug. iii. (1778) p. 4(55, pi. c.«viii. ; 



Desm.'Maium. i. (1820) p. 189; Harlan, Faun. Amer. (1825) p. 72. 

 Lutra stelleri, Lesson, Mamm. (1827) p. 156, no. 423. 

 Enhydra marina, Fleming, Philos. Zool. ii. p. 187 ; Martin, P. Z. S. (1836) 



p. 59 ; Aud. & Baohmau, N. A. Quad. iii. p. 170, pi. cxxxvii. ; Baird, M. 



North Am. (1857) p. 189. 

 Enhydris marina, Licht. Darstell. Saug. (1827) p. 34, pis. 49 and 50; Wag- 

 ner's Supp. ii. p. 268 ; P. Gervais, Mamm. ii. p. 119. 

 Enhydris stelleri, Fischer, Syn. (1829) p. 229. 

 Enhydris lutris, Coues, Fur-bear. Anim. p. 326. 

 Lutra {Enhydra) marina, Richardson, F. B. Am. i. (1829) p. 59, no. 21 ; id, 



Zool. Beechey's V. (1839) p. 5. 



