366 



U. S. P. R. R. EXP. AND SURVEYS ZOOLOGY GENERAL REPORT. 



fins are more developed, although alike in shape. The anterior margin of the first dorsal is 

 somewhat nearer the extremity of the snout than the anterior margin of the second dorsal, which 

 is nearly equidistant between the tip of the caudal fin and the orbit. The origin of the anal fin 

 is nearly equidistant between the tip of the caudal and the posterior end of the insertion of the 

 pectorals ; its posterior extremity reaches the anterior margin of the first portion of the lower 

 lobe of the caudal, and which we should be inclined to consider as a second anal fin. The origin 

 of either lobe of the caudal fin is almost even ; the inferior lobe is much deeper anteriorly than 

 the upper. The posterior portion of the lower lobe of the caudal is much smaller than the 

 anterior portion. It is exteriorly rounded or sub-truncated, and separated from the upper lobe 

 by a small incision, which corresponds to the tip of the vertebral column. The posterior margin 

 of the ventrals, which is sub-truncated or sub-concave, extends somewhat beyond the origin of 

 the second dorsal. The posterior edge of the pectorals is sub-convex or rounded off; its middle 

 region approximating the origin of the ventrals when bent in that direction. The vent is lon 

 gitudinal, and placed between the ventral fins. 



The upper surface of the body and fins is very rough to the touch ; the scales, or rather dermic 

 productions, are very small, and irregular in size and shape. They are more conspicuous over 

 the supra-ocular ridges and the dorsal region, properly so called, where some of them are raised 

 above the others ; they are smallest over the fins and sides of the body ; but whether triangular, 

 sub-rhombic, or cruciform, the angles are always acerated, the points being sometimes a con 

 tinuation of a minute keel, which start from the middle of the scales. Over the inferior surface 

 of the head, body and horizontal fins, the scales are sub-rhombic or sub-cordiform, likewise 

 variable in size, exhibiting but one single inconspicuous keel, without angular points ; hence 

 that surface assumes quite a smooth aspect. The scales, moreover, are closely approximated, 

 sub-imbricated, whilst on the upper surface of the body they are almost all isolated. The 

 color above is yellowish grey, darker in the young; beneath light yellow. Small roundish, 

 black spots, are spread all over the body and fins. 



List of specimens. 



Family NOTED AN1DAE, Owen. 



The head is flat or depressed. The nostrils are provided with a small, triangular flap. A 

 very large fold or wrinkle at the upper (anterior) angle of the mouth ; a smaller one at the 

 lower (posterior) angle ; nictitating membrane wanting ; tongue immovable. The spiracles 

 are small and vertical. The branchial apertures are six or seven in number, diminishing gradu 

 ally in size from forwards backwards, all of which are placed in advance of the base of the pec 

 toral fins. A tooth at the symphysis of the lower jaw ; the next five or six teeth on the lower 

 jaw constitute on either side a saw, directed from upwards and inwards, downwards and out 

 wards. The anterior or inner edge of the teeth is smooth or very finely serrated. The outer 

 most teeth of the jaw are low and depressed. The teeth at the upper jaw are more elongated, 

 smaller and more acute ; the first prong or point is much longer than the rest ; their outer 



