28 CALIFORNIA ACADEMY OF SCIENCES 



rounded posteriorly. In the former case it is not infrequently continued backward 

 onto the dorsal plate. The granulations are always very fine; they are sometimes 

 arranged in serie.>^, and are always rather distant and inconspicuous. 



The teeth on the palate are especially variable. The vomerine patches are 

 usually small, and may be either confluent with each other and with the palatine 

 patches, or may be separated from both by a groove. This variation seems to be not 

 determined by age. The palatine patches are sometimes ovate, small, with very 

 indistinct backward processes; sometimes fully twice as large, produced backward, 

 with their inner margins nearly straight and diverging. 



The snout is usually broadly rounded or subtruncate, seen from above. In 

 some cases, however, it is sharply convex, the mouth then with more lateral cleft, 

 and often with swollen lips. In all the specimens, the premaxillary band of teeth is 

 long, its width being contained not less than four times in the length. The barbels 

 are always short, the maxillary barbel seldom reaching the gill-opening. In adults, 

 the appearance is often peculiarly modified by the great enlargement of the upper 

 portion of the cheek muscles, making the top of the head transversely concave. 



The long adipose fin is highest near its middle, where the vertical height is about 

 one-third the length. The fin is not wholly adnate, there being a short, free posterior 

 border. It is constantly a little longer than the base of the first dorsal. 



43. Netuma platypogon {Giinther). 



Abundant in the Panama mai'ket. Of the ten specimens preserved, six are 

 females, with elongate ventrals, which overlap the front of the anal. Unlike 

 G. eigenmanni, the vent is constant in position, not more anteriorly placed in 

 females. As in G. eigenmanni and G. jordani, the inner ventral ray is somewhat 

 broadened in females, and gives attachment to a dermal thickening, less marked, 

 however, in this species. 



In one male specimen taken at some date between January 10 and February 

 24, the mouth contained eggs, and was obviously functioning as a brood-cavity. 

 The strong arch to the buccal roof was evident. It is clear that the breeding season 

 is not confined to June and July, as given by Steindachner (1876 b, p. 17). 



N. platypogon has the basal portion of the paired fins jet black on their upper 

 surfaces, in both males and females. The anal is blacki.sh in its anterior two-thirds, 

 with a wide white margin. The fontanel groove is everywhere sharply defined. It 

 is widest a little in front of the middle of its length, tapering slowly backward to the 

 base of the occipital plate, the base of which is always readied. Anteriorly, it 

 narrows more rapidly, terminating in an acute point which is opposite or in advance 

 of the middle of the eyes. 



The dorsal spine is very narrowly compressed, its anterior margin sharp, 

 strongly serrate. 



44. Netuma oscula (Jordan <i- Gilbert). 



Two specimens are distinguishable from N. jylaniceps only by the smaller 

 mouth and the shorter band of premaxillary teeth. The widtii of the latter (antero- 



