572 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 112 



to the recognition of a third nominal species of this group, Astroscopus 

 anolopos, apparently based on a small specimen of A. y-graecum that 

 still had the larval character of the head covered by the exposed cranial 

 bones. We have not examined larval specimens of A. guttatus and 

 therefore cannot distinguish them from larval A. y-graecum other than 

 by distribution. Larval specimens of Astroscopus from the North 

 Carolina coast, where the ranges of the two species are known to 

 overlap, are identified only to genus; specific identifications of larvae 

 from north and south of North Carolina are presumptive. In a 

 publication containing many life history notes and theories, Dahlgren 

 (1 927) discussed both Astroscopus y-graecum and A. guttatus and stated 

 (p. 364): "Where they overlap in the neighborhood of Cape Hatteras 

 it seems practically certain that they interbreed, and great variation 

 is found." Dahlgren did not, however, record his criteria for separa- 

 tion of the two species, and we are convinced that he misidentified 

 some of his specimens (see synonymies). 



Diagnosis: Dorsal spines III to V. Dorsal soft rays 13 to 15. 

 Anal soft rays 12 to 14. Pectoral ra} T s 19 to 22. Pelvic rays I, 5. 

 Pelvic girdle without exposed anteriorly directed spines. Top of head 

 covered by exposed cranial bones to about 31 mm. S.L. ; in larger sizes 

 the frontal bones exposed posteriorly on the head, with their medial 

 processes forming an exposed Y-shaped process that extends anteriorly 

 between the eyes, and with the area within the fork of the Y and lateral 

 to it covered by skin; with growth the basal arm of the Y becomes 

 long and narrow and the fleshy area becomes comparatively large; 

 least width of the basal arm of the Y about 1.4 to 2.4 percent of stand- 

 ard length at sizes larger than 100 mm. S.L. Posterior nostrils each 

 in a fringed groove curving around behind the eye; posterior end of 

 nostril groove much closer to back of eye than to posterior margin 

 of skin-covered area over electric organs; distance from eye to end of 

 rear nostril groove (a in plate la) into distance from end of rear nostril 

 groove to posterior margin of skin- covered area (b in plate lo) about 1.9 

 to 11.0 times (in sizes above 40 mm. S.L.). Lower jaw without a pair 

 of prominent converging bony ridges. 



Preoperculum and operculum without spines or processes above 

 about 35 mm. S.L. (in smaller sizes the preoperculum has a blunt 

 angle spine, and a bluntly pointed spine is present at the upper anterior 

 margin of the operculum) . Cleithral spine small, laterally compressed, 

 covered by skin and adpressed to body. Scales present on body and 

 extending onto fleshy part of caudal fin; scales absent on head, an area 

 posterior to the pectoral fin bases, the throat and abdomen, between 

 the lateral lines and the dorsal fin, and a narrow area along the anal 

 fin base. Lateral lines on each side of body extending from head 

 along back close to dorsal fin, bending down through central part of 



