APPENDIX C. 
215 
for tlie respiration of these fishes^ so that they are obliged to eome 
to the surface at certain intervals^ to receive an additional quantity 
of atmospheric air. 
Ophiocephalus ohscurus, Gthr. (Plate II. ^ Fig. B.) 
D. 42. A. 26 — 29. L. lat. 70. L. transv. 7/14. 
The height of the body is nearly one-eighth of the total length, 
the length of the head nearly one-fourth ; the width of the inter- 
orhital space is more than the extent of the snout, and one-fourth 
of the length of the head. The cleft of the mouth is wide, the 
maxillary extending behind the orbit. The scales on the upper sur- 
face of the head are of moderate size, those on the neck small; 
there are thirteen series of scales between the orbit and the angle 
of the prseoperculum. The pectoral does not extend on to the 
origin of the anal, and its length is one-half of that of the head; 
the length of the ventral is three-quarters of that of the pectoral. 
Caudal rounded, its length being six times and one -third in the 
total. Blackish, lighter below, vrith dark streaks along the series 
of scales ; a series of black blotches along the side ; head with two 
indistinct oblique black spots along its base. Pectoral and ventral 
variegated with blackish. Chin black, with white- spots. 
Length seventy-seven lines. Collected at Gondokoro. 
