I20 PATAGONIAN EXPEDITIONS : ZOOLOGY. 



"Description Physique de la Republique Argentine," gave a series of 

 figures of skulls of old and young of both sexes, showing individual and 

 sexual variation, and also variation due to age. This is a most important 

 series of figures, based on specimens from the Lobos Islands, ofT the 

 mouth of the Rio de la Plata. 



In 1892 Philippi figured a number of skulls, including those of three 

 supposed new species, all, however, based on very young animals, several 

 of the skulls showing part of the milk dentition, besides other features 

 of immaturity. 



Otaria byronia has thus been very fully and satisfactorily illustrated as 

 regards both its external characters and internal structure. 



Genus ARCTOCEPHALUS F. Cuvier. 



ArctocepJiale, F. Cuvier, Mem. du. Mus. d'Hist. Nat, XI, 1824, 205, pi. 



XV, fig. I , a, b, c. 

 Arctocepiialus F. Cuvier, Diet, des Sci. Nat, XXXIX, 1826, 554. Same 



as above. Type, " Phoca nrsiiia" = Phoca antayctica Thunberg. 

 Halarctus Gill, Proc. Essex Inst., V, 1866, 7, 11. Type, AyctocepJialus 



delalandi Gray = Phoca autarctica Thunberg. 

 ArctopJioca Peters, Monatsb. Akad. Berlin, May, 1866, 276 (subgenus 



of Otaria). Type, Otaria \AyctopJioca\ pJiilippii, sp. nov. 

 Etwtayia Gray, Ann. & Mag. Nat. Hist. (4), IV, Oct., 1869, 269 ("South 

 America") ; Suppl. Cat. Seals and Whales, 1871, 20. Type and only 

 species, AyctocepJialus nigyescens Gr^y = Phoca fa/ktandica Shaw. 

 Gysophoca Gray, Ann. & Mag. Nat. Hist. (4), IV, Oct., 1869, 269 

 ("Australia"); Suppl. Cat Seals and Whales, 1871, 24. First spe- 

 cies, Otaria [AyctocepJialus) cineyea Peters = ? Otayia cineyea Peron, 

 1816= Otayia cineyea Quoy & Gaim., \^2P = Otayia foysteyi Lesson, 

 1828. 

 The only species referred by F. Cuvier (/. c, 1826) to his genus 

 AyctocepJialus is his ''AyctocepJialus uysinus ; L/ysus mayiuus, Steller, 

 Novi comment petrop., 11, p. 331," which he elsewhere mentions as 

 " PJioca uysina, Linn.," and distinctly says is the type of his genus Aycto- 

 cepJialus} On this account many subsequent writers have given the type 

 of Ayctocephalus as PJioca uysina. Lender this name, however, Cuvier 

 associated not only Steller's Sea Bear, but the Fur Seal observed by Per- 



' Mem. du Mus., XI, 1824, p. 208; Diet, des Sci. Nat, XXXIX, 1826, p. 553. 



