no. 2075. FISHES FROM SOUTHERN CALIFORNIA— GILBERT. 343 



AVERRUNCUS EMMELANE Jordan and Starks. 



Xystes axinophrys Jordan and Starks, Proc. Cal. Acad. Sci., ser. 2, vol. 5, 1895, 

 p. 824, pi. 92. 



Station 4520, Monterey Bay, 32-44 fathoms. 



A single young specimen from the above station affords a notable 

 extension in the range of this species, known hitherto only from 

 Puget Sound. The fin-rays are as follows: Dorsal, X, 8; anal, 12; 

 pectoral, 14; ventral, I 2. 



Examination of the type of Xystes axinophrys Jordan and Starks 

 has shown that it is based on a very young individual of Averruncus 

 emmelane. 1 The only full characterization of Xystes is that given by 

 Jordan and Evermann. 2 It is said to differ from Averruncus by the 

 shorter vertical fins, the last rays of which are without posterior 

 membrane; the progressively shortened lower rays of the pectorals; 

 the absence of barbels or nuchal pit; the presence of a strong knife- 

 like spine above eye. The vertical fins are, however, of the same 

 length, the fin formula agreeing exactly (the anal fin in the type of 

 Xystes having 11 instead of 10 rays). The last rays of dorsal fins 

 are attached by posterior membrane, as in related forms, this mem- 

 brane ruptured in the type of Xystes. The lower pectoral rays are 

 progressively shortened in the young of all Agonoids, a specimen of 

 A. emmelane from Annette Island, Alaska, 105 mm. long, showing 

 as yet no trace of the elongation of these rays. Barbels are present 

 in the type of X. axinophrys, covering the lower jaw and the bran- 

 chiostegal membranes and agreeing in position with those in A. 

 emmelane. A nuchal pit is present, though less developed than in 

 adults. All the spines on head are larger in the young, but those in 

 X. axinophrys agree wholly in number and position with those in 

 A. emmelane. There can be no doubt of the identity of the two 

 species. 



Averruncus sterletus Gilbert should probably be referred to the 

 genus Agonopsis, which appears to differ from Averruncus in the 

 shorter vertical fins and the subequal jaws, the rostrum not conspicu- 

 ously protruding. The latter character is not very important, and 

 the two genera eventually may be united. 



ASTEROTHECA, new genus (Agonidae). 



Type of the genus. — Xenochirus pentacanthus Gilbert. 3 

 Like Xeneretmus (for Xenochirus Gilbert, preoccupied) in all 

 respects except that the terminal rostral plate is very small, not pro- 

 jecting beyond the premaxillaries, and bears 5 small spines, 3 of 

 which diverge upward and backward and 1 projects freely at each 



1 See also Starks, Ann. Carnegie. Mus. vol. 7, 1911, p. 195. 



* Fishes of North America, p. 207C. 



• Proc. U. S. Nat. Mus., vol. 12, 1890, p. 91. 



