134 PATAGONIAN EXPEDITIONS: ZOOLOGY. 



In 1 87 1 Philippi based the name Otaria [ArctopJioca) argeiitata on a 

 specimen from Juan Fernandez Island which Dr. Peters and subsequent 

 writers generally have considered as representing the female of A. philip- 

 pii. The same author in an article entitled "Las Focas Chilenas" (An. 

 Mus. Chili, 1892, pp. 52, pll. 23) has recognized five or six species 

 of fur seals from the coast and islands of Chili, all apparently referable to 

 those previously known from the Chilian coast. Among these are two, 

 both based on immature specimens, described as new, namely (i) Otaria 

 brachydactyla, from the Chonos Archipelago, founded on a suckling pup 

 still retaining the milk dentition, and too immature for determination by 

 the description and figures (see aiitea, p. 126) ; and (2) Otaria leiicostoma 

 from Mas a Fuera, of which the skull is not figured. It is apparently a 

 female or a young male oi Arctoceplialus pliilippii. 



In 1904 the Fur Seals of the Galapagos Archipelago were separated 

 by Heller (/. c.) as a distinct species under the name Arctoceplialits gala- 

 pagoeusis, on the basis of certain supposed cranial differences distinguish- 

 ing it from A. pliilippii. His comparison must have been made with 

 Peters's description and figures of the skull of A. pliilippii, which I had 

 already considered with care in reference to a good series of Galapagos 

 skulls, without feeling myself warranted in making the separation later 

 proposed by Mr. Heller. His alleged characters — "wider skull, both 

 the zygomatic and mastoid measurements being considerably greater, and 

 by longer snout and mandible" — are not evident. While his measure- 

 ments of an "old adult" male skull are larger than those given by 

 Peters, it must be recalled that the type skull of A. pliilippii was, while 

 "full-grown," "not very old."^ The differences in size and proportions 

 are only what might be expected in skulls of the same species of cor- 

 responding ages. While the Galapagos animal may very naturally be 

 different on geographical grounds, from that of the Juan Fernandez 

 Islands, as already intimated [aiitea, p. 123), any diftcrences that may ex- 

 ist can be shown only by direct comparison of satisfactory material from 



A skull from Jarvis Island, Galapagos Archipelago, has six teeth on the left side and only five 

 on the right, set in close ju.xtaposition. 



The emargination of the palatal border, in varying degree, is a not very uncommon condition 

 in Pinnipeds which have normally the palatal border truncate or only slightly concave. 



' " . . . dem Schadel eines augsgewachsenen, aber noch nicht sehr alten mannlichen Ex- 

 emplars." — Peters, Monatsb. Akad. Berlin, i866,p. 276. 



