RICHARDSON and JOSEPH: LARVAE AND YOUNG OF BOTHIDS 



Table 2. — Total numbers of adult Einipu.s Diicrosioiuns and Ciiharichihys arctifruns (and per- 

 centage of these two species combined in parentheses) compared with total numbers of bothids 

 and scophthalmids and all flatfishes collected in the Chesapeake Bight during 1966.' 



' From Virginia Institute of Marine Science trawl data. 



DISTINGUISHING FEATURES OF 



E. MICROSTOMUS AND 



C. ARCTIFRONS LARVAE 



Characters useful in distinguishing and sep- 

 arating lar^vae of E. niicwHtomus and C. arcti- 

 fro)is taken in the Chesapeake Bight are listed 

 in Table 3. Larvae <4 mm are most easily 

 separated by the presence of preopercular 

 spines in E. microstomus. Larvae >4 mm are 

 best separated by pigment patterns (C. arcti- 

 fro)is has less pigment in general than E. micro- 

 stomus) and the presence of three elongated 

 anterior dorsal fin rays in C. arctifrons. 



The number of myomeres, which usually 

 corresponds to the number of vertebrae, is 

 frequently a valuable character for identifica- 

 tion of larvae. In this study, myomeres were 

 usually impossible to count on specimens <4 

 mm because the segments, especially those on 

 the most anterior and posterior parts of the body, 

 were indistinct. The same was true of many 

 larger specimens. When accurate counts were 

 possible, the number was always less than verte- 

 bral numbers, i.e., E. microstomus — 31-33 

 myomeres (34-35 vertebrae) and C. arctifrons 



— 34-35 myomeres (36-39 vertebrae). Speci- 

 mens selected for illustration were the best 

 representatives and all had rather well-defined 

 myomeres. Myomeres are still visible in juve- 

 niles of 40 mm (see Figure 7) mainly because 

 of the deciduous nature of the scales. However, 

 scales or scale pockets, particularly in the an- 

 terior abdominal region, tend to obscure them. 



EGGS AND YOLK SAC LARVAE 



OF E. MICROSTOMUS AND 



C. ARCTIFRONS 



Eggs of E. microstomus and C. arctifro)is 

 have not yet been identified in plankton samples. 

 Attempts to strip, fertilize, and rear eggs of 

 both species have been unsuccessful. 



None of the ovaries examined of several 

 hundred mature specimens of E. microstomus 

 was running ripe. Eggs taken from the ripest 

 ovaries were still hard, opaque, and quite small. 

 They were approximately spherical with no 

 apparent oil globule. Eggs stripped from C. 

 arctifrons which were approaching spawning 

 condition were pliable and almost transparent. 

 They were spherical to slightly ovoid, with a 



739 



