588 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 



they appear as blotches; sides ofteii \vith much light yellow; axil of 

 pectorals black. Body oval, compressed, with thick short caudal pe- 

 duncle and very short head. Profile moderately depressed above the 

 eyes. Spinous dorsal rapidly rising to the fifth or sixth spiiie, thence 

 gradually descending; spiuous dorsal higher than soft part; cheeks 

 with scales in 2i series. Head 3 ; depth 2. D. IX, 14 ; A. Ill, 16 ; Lat. 

 1. 45. L. C inches. Pacific coast of United States; common; the small- 

 est of the family. 



(C'ljmatogaster minimus Gibbous, Proc. Acad. Nat. Sci. Phila. 1854, 125: Abeona irow- 

 In-idgii Girard, U. S. Pac. R. R. Surv. Fish, x, 186, pi. 34, n'g. 6-10 : Ditrcma minimum 

 Giiutber, iv, 249.) 



925. A. aurora Jordan & Gilbert. 



Color bluish-black above, becoming lighter on sides and silvery be- 

 low. Opercles and lower half of sides punctate with black dots and 

 shaded with light orange, the latter more intense on the centres of the 

 scak'S and forming a diffuse lateral baud; a broad grayish streak back- 

 wards from pectorals to opposite origin of anal, this streak without orange 

 tint and with the margins of the scales dark by aggregation of black 

 points ; young specimens with the bright lateral shade more distinct, 

 and rosy instead of orange; fins marked with more or less blackish, the 

 anal with some yellowish; a conspicuous black triangular blotch in the 

 axil of the pectoral. Body elongate, with a very long and rather thick 

 caudal peduncle. Head transversely very convex above, and with a 

 blunt snout. Mouth small, oblique; maxillary reaching but two-thirds 

 the distance to front of orbit. Spinous dorsal with the fifth to the ninth 

 spines highest, and about equal to the longest soft ray. Caudal forked 

 for nearly half its length. Scales on cheeks in 3 distinct series. Head 

 4 ; depth 2 : >. D. IX, 17 ; A. Ill, 20 ; Lat. 1. 45. L. 7 inches. Monterey 

 P>;iy. California ; abundant in rock-pools. 



(Jordan & Gilbert, 1'roc. U. S. Nat. Mils. 1880,299.) 



312. JTIICROITIETRUS Gibbous. 



Sparadat. 



(Ciliii<ilo(jnxttr and Hniclu/ixfinx (Jill: Mttroijaxlir A.trassiz.) 



i (Jil. linns, I'ruc. Ciil. Ai-.-id. \.-il. Sci. iu D:iilv 1'laccr Times and Transcript, May 30, 

 1 -." 1: t\ |M- ('i/iiiiit<>i/ii*t<-r iiyi/ri'i/itliiN Gibbons.) 



Body elliptical, oblong, compressed. Head conic. Mouth small, 

 oblique, the lower ja\v slightly shorter; lips thin, the lower with narrow 

 tiemiiii or none: teeth small, conical, rather numerous, in one series, 

 (lill-rakers moderate, slender. Scales comparatively large. Dorsal 



