Hubbs — A Revision of the Viviparous Perches. 13 



A*. — Anal fin of male containing more rays than that of female;* a 



large oval depression with a well-defined rim, on body near front of 



anal fin; the skin thickened in this depression, and the sheaths 



about cylindrical muscles lying beneath the skin bound to it; t an 



oval gland-like body with an anterior horn developed on each side of 



fin, connected with other structures as in the Embiotocinae; anal 



rays crowded anteriorly, but none modified into a triangular plate. 



Teeth of the jaws tricuspid, uniserial ; intestine longer than in other 



groups ; the two species herbivorous Micrometrinae, new subfamily. 



a 1 . — Scales over oval depression near front of anal fin in male minute ; 



scales also decreased in size in the corresponding area in the female ; 



scales, 43 to 47 (53 in one specimen) along lateral line; difference 



in the number of soft rays in the anal fin of the two sexes less (18 



to 20 in the female; 21 to 23 in the male);* dorsal rays VIII 



(sometimes VII or IX), 17 to 19 ;+ the first three spines abruptly 



graduated, the last five subequal; outlines of body subelliptical 



Amphigonopterus § aurora (Jordan and Gilbert). 

 a 2 . — Scales over oval depression near front of anal fin in male rather 

 less reduced in size; scales, 34 to 42 (47 in one specimen); differ- 

 ence in the number of soft rays in the anal fin in the two sexes 

 somewhat greater (13 to 18 in the female; 20 to 23 in the male) ;|| 

 dorsal rays IX or X (rarely VIII), 12 to 15;|| the median spines 

 strengthened and elevated ; outlines of body subrhomboidal 



Micromelrus^ minimus (Gibbons). 



* But one other instance of this kind in the whole class of fishes has come to the 

 writer's attention: it is that of the South American Poecilioid genus Cynolebias (see 

 Regan, Ann. Mag. Nat. Hist., ser. 8, 10, 1912, pp. 641-642). 



t No gland was found beneath this depressson by gross dissection. 



t About 90 specimens counted. 



§ Amphigonopterus, new genus; genotype, Abeona aurora Jordan and Gilbert, a 

 species inhabiting the rock-pools of the central California coast. 



II About 90 specimens counted ; the variation is extraordinarily wide for a spiny- 

 rayed fish. 



IT Concerning the use of Micrometrus Gibbons, in place of Abeona Girard, see Jordan 

 (Copeia, No. 49, 1917, p. 86). 



