300 U.S. NATIONAL MUSEUM BULLETIN 2 02 Vol. 2 



principal caudal rays branched; pectoral formula variable, typically 

 iii,6,vii, but often ii,7,vii or iv,5,vii; first unbranched pectoral ray long- 

 est, lower 7 thickened; pelvic rays two, inner ray the longer; pelvic 

 rays bound together by a membrane for approxim.ately % the length 

 of the outer ray and somewhat more than % the length of the inner ray; 

 spines of first dorsal gi-aduated, lower than second dorsal; outline of 

 second dorsal even, fu'st spine almost as high as longest (third or 

 fom-th), rays subsequent to fifth gradually decreasing in height; third 

 dorsal soft ray longest; anal spine slightly less than % as long as first 

 anal ray; scales ctenoid, scalation reduced, no scales on head, nape, 

 belly or pectoral base; a wide naked band under first and second 

 dorsals, narrowing gradually, so that upper sides are completely scaled 

 only back of the second dorsal; a naked band above anal continuing 

 the length of the fin, but ending at last ray of anal, so that lower surface 

 of caudal peduncle is scaled. 



Some sexual dimorphism of body proportions is present in this 

 species. The dorsal fins of males are, on the average, slightly higher 

 than those of females. More important, however, is the dimorphism 

 in the length of the belly and the anal base. The distance between 

 the pelvic and anal origins is greater in females (average for 9 females 

 312, average for 12 males 280), while the anal base is shorter (average 

 for 9 females 405, average for 11 males 426). The number of anal 

 rays appears to be the same in both sexes. 



On the basis of the material available to me, the maximum size 

 attained by this species is about 31 mm. The smallest mature male 

 in my material is 25.5 m.m. standard length, and the smallest matiu-e 

 female 25.0 mm. All specimens below this size are clearly immature. 



Color in alcohol. — Male with body a clear translucent pink wath 

 only a few scattered melanophores, mostly below the lateral line on 

 the anterior part of the sides. Pectoral base dark, pigment most 

 concentrated on lower % of pectoral base, forming a triangular black 

 spot which encroaches on the pectoral rays. Sides and lower surface 

 of head dark, as is the throat back to the pectoral base. Interorbital 

 and top of head pink "with a few scattered melanophores. Pelvic rays 

 dark for about % the length of the inner ray. Margins of dorsal fins 

 dark, anal dusky, this coloration more intense at the margin. Caudal 

 clear. Female and juvenile male with body pink; head, breast and 

 pectoral base with a few scattered melanophores; fins clear, or with a 

 few scattered dusky spots. 



Remarks. — In addition to the characters mentioned in the key, 

 H. capidata differs from H. chica in size at sexual maturity and maxi- 

 mum size, coloration of vertical fins, number of rays in second and 

 third dorsals, number of anal rays, and number of pored scales in 

 lateral line. 



The name refers to the hooded appearance of the dark-headed males. 



