450 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



Total. — The adult complement of total number 

 of gill rakers (25-27) was reached by 40 nnn. 

 (table 16, p. 449). 



Lower limb. — The adult complement (17-19) 

 also was attained by 40 mm., but the percentage of 

 specimens with 19 continued to increase through 

 150.00 mm. (table 17, p. 449) . 



Ceratohranchial hotie and comparison loith M. 

 martinicus. — The data indicate that the juveniles 

 of U. parvus and M. ma^^tinicus may be separated 

 on gill raker counts. The gill rakers of U. parvus 

 are plotted against those of M. martinicus to show 

 both the number of gill rakers on the lower limb 

 and the number of gill rakers on the cerato- 

 hranchial bone (fig. 35). The latter character 

 shows less intraspecific variation than the former. 

 The terminus of the ceratohranchial bone was 

 determined by manipulation of the gill arch and 

 observation of the point that the break occurs be- 

 tween the ceratohranchial and basibranchial bones. 

 The gill raker that may seem to occur between the 

 two bones is included in counts for the cerato- 

 hranchial bone. 



The graphs show a clear separation of the 

 species U. parvus and M. inartinicus. Up to a 

 size of 34 mm., U. parvus possessed 10 to 12 gill 

 rakers on the ceratohranchial bone, and 11 or 12 

 after this size. Above 82 mm., M. martinicus had 

 14 to 15, except for a 107-mm. specimen with 12 

 gill rakers on the right side (the side normally 

 counted) but 14 on the left. The maximum num- 

 ber of lower-limb gill rakers in U. parvus was 19, 

 and the minimum in M. martinicus was usually 20 

 or more (one specimen of M. martinicus had 19). 



Teeth 



Upper jaw. — Teeth were present in the upper 

 jaw of all the specimens examined; the smallest 

 was 20.8 mm. 



Lower jaw. — No teeth were evident in the lower 

 jaw of the 20.8- or 21.f5-mm. specimens and one 

 28.0-mm. specimen, but were seen in all others. 



Vomerine. — No teeth were apparent on the 

 vomerine bone in a stained specimen of 44.0 mm., 

 but they had formed in the 45.6-mm. specimen. 

 Small teeth were present in all juveniles larger 

 than 44 mm., with the exception of one 52.5-mm. 

 specimen. 



Palatine. — The palatine teeth seemed more vari- 

 able than the vomerine in the time of their forma- 

 tion. They were present in a 45.4-mm. juvenile 



and in all of the specimens over 53.8 mm., but in 

 the interval between these sizes some of the speci- 

 mens had them and some did not. In the more 

 mature forms, the number of palatine teeth in- 

 creased rapidly, and the palatine bones of the 

 adults presented coarse, slightly pointed, peglike 

 teeth which were very much more numerous than 

 the vomerine teeth. 

 Scales 



Counts were possible on only a few specimens as 

 the scales are very deciduous. A 22.0-mm. speci- 

 men, however, had 37 fully developed ctenoid 

 scales in the lateral line, which is within the adult 

 complement (36 to 38) (Lachner, 1954). 



A 56-mm. specimen had 10 ctenii on the margin 

 of one of the scales, and there were 55 on a scale 

 of a 129.5-mni. specimen. 

 Barbels 



In the smallest specimen, 20.8 mm., the right 

 barbel was completely free of the branchiostegal 

 membrane, but the left had not yet separated. The 

 21.6-mm. specimen had both barbels still attached. 

 The 22.2-rmn. specimen had the left barbel at- 

 tached completely and the right barbel almost 

 free, but still attached at the distal end. The 

 23.3-mm. and larger specimens had perfectly 

 formed barbels free of the membrane. Thus, in 

 U. parvus we have somewhat earlier development 

 of the barbels than in M. harhatus or M. surmul- 

 letus as described by Lo Bianco (1907). 

 Operculum 



No opercular spine was present on any specimen 

 examined, although there was a projection of the 

 opercular bone (fig. 38) in the same location as 

 the opercular spine of P. maculatus and M. mar- 

 tinicus (figs- 23 and 43). 

 Cleithrum 



IVlien the scales were removed the cleithrum 

 (fig. 38) was revealed as a prominent bone without 

 the serrations found on the upper wing of the 

 cleithrum of P. maculatus (fig. 23) . 



SPAWNING 



The gonads of mature specimens, one male, 120 

 mm., and two females, 130 and 135 mm., taken by 

 bottom trawl at 29 fathoms, June 3, 1954, in the 

 Gulf of Mexico were found to be between stages 

 IV and V in their development (the eggs or milt 

 fill from one-half to the entire body cavity) using 

 the classification given by Broadhead (1953). 



