NO. 3582 GENUS ENTOMACRODUS — SPRINGER 137 



New Georgia, New Britain, and Waigeo may have the midportion of 

 the ventral margin of the upper lip very weakly crenulate. A great 

 deal more material from many localities will be necessary to determine 

 if any of the populations merit naming. The two most obviously 

 distinct groups are the Tahiti-Makatea-Raroia-Rarotonga group, 

 which lacks a humeral blotch, and the New Georgia-New Britain- 

 Waigeo group, which shows the dark-spotted color pattern associated 

 with a high anal ray count, shorter dorsal spine three, shorter dorsal 

 ray one, shorter horizontal humeral blotch length, and, in some speci- 

 mens, a weakly crenulated midportion of the upper lip ventral margin. 



It can be assumed from the population variations noted that there 

 is relatively little dispersal and interbreeding among the various 

 island populations. There is no information available to explain the 

 initial and subsequent factors that distributed this species and then 

 isolated the various populations. Why the South China Sea speci- 

 mens are similar to the populations much farther to the east in the 

 Pacific, in spite of the presence of the intervening and different 

 Philippine-Palaus populations, requires attention. One would expect 

 the South China Sea populations to have diverged — perhaps most of 

 all— in view of the fact that two (E. thalassinus and E. stellijer) of 

 the other four species of Entomcarodus present in that area are repre- 

 sented by endemic subspecies. Perhaps the South China Sea popu- 

 lation of E. caudojasciatus has in fact diverged, but along parallel 

 rather than derivative lines, from that population which gave rise to 

 the Pacific populations to w^hich it bears resemblance. One cannot 

 exclude the possibility, however, that the South China Sea and 

 Pacific populations represent a relict distribution or a once more 

 widely distributed form. 



Discussion. — The spotted appearance of the body and nature of the 

 upper lip crenulations of the specimens from Waigeo and New Georgia 

 caused Chapman (1951, p. 285) to mistakenly identify these specimens 

 as E. striatus. The pattern of spots on the body of E. striatus is of an 

 entirely different nature (pis. 7c, d, 12) than that of these specimens 

 (plate 27, of a New Britain specimen, exhibits the same type spotting 

 as does the New Georgia and Waigeo specimens). When a humeral 

 blotch does occur in specimens of E. striatus, it is never so distinct or 

 relatively so large as that of specimens of E. caudofasciatus. Speci- 

 mens of E. striatus have a distinct dark spot behind the eye, a mark 

 not found in E. caudojasciatus specimens. The gill-raker count of 

 14-16 in the Waigeo-New Georgia specimens is at the extreme low 

 end of the range for E. striatus. In 84 specimens of E. striatals, 25.0 to 

 34.9 mm SL, the predorsal commissural pores ranged from 2 to 6 (only 

 6 specimens with 5 pores and 1 with 6) while the 3 Waigeo-New Geor- 

 gia specimens, 27.0 to 29.0 mm SL, had 4, 7, and 9 predorsal com- 



