172 PROCEEDINGS OF THE ACADEMY OF 



The eye is elliptical, and its diameter is contained 6| times in the head's 

 length. The distance of the posterior nostril from it equals a diameter. The 

 maxillary barbels extend to about the middle of the pectoral ; the outer mental 

 to its base, and the inner mental are two-thirds as long as the outer. 



There are three villiform patches on the palate which are almost contiguous, 

 and together describe arch in front ; the median patch is small, rather trans- 

 verse and widest towards the front ; the outer are oblong, subtriangular. The 

 band of the upper jaw is nearly uniform and quite wide ; the lower, interrupted 

 at the symphysis, is nearly half as wide as the upper, and is narrowed towards 

 its ends. 



The dorsal spine enters 1 J times in the head's length, has in front, first, minute 

 teeth pointed downwards, and then a row of small pisiform tubercles ; teeth 

 pointed downwards on its hinder border. The first ray is little higher than 

 the spine. The anal commences at a distance from the snout 3f times as great 

 as that from the base of the caudal fin ; its length enters 6$ in the length, ex- 

 clusive of the caudal, and when bent back, it reaches to the supernumerary 

 caudal rays ; the greatest height nearly equals the length. The pectoral fins 

 extend rather beyond the base of the dorsal and exceed a fifth of the length, 

 exclusive of the caudal; the spine equals that of the dorsal. The ventrals are 

 inserted midways between the base of the pectoral spines and the axil of the 

 anal, and extend to the origin of the anal. 



D. I. 7. A. 16. C. 11. I. 6. 7. I. 11. 



The fins are almost blackish. 



A single specimen is in the collection. 



Genus AELURICHTHYS B. and G. 

 Pimelodus Bleeker, nee Cuv. et al ex Lac. 



Aklurichthys panamensis Gill. 



The greatest height iB contained 5 times in the length to the base of the 

 eaudal fin, and 6^ times in the total. The height of the caudal peduncle equals 

 half the interorbital area, and is half its length behind the anal fin. The 

 smooth head enters 4 times in the length to the middle of the central caudal 

 rays, and nearly 5 times in the total. 



The width of the head enters 1 J times in its length, and the width of the 

 interorbital area If. The eye is elliptical ; its diameter equals a fourth of the 

 head's length, and the distance from the anterior nostril is equal to it. The 

 maxillary barbels extend backwards nearly to the anus, and the mental to the 

 bases of the pectoral fins. 



The dorsal buckler is rather longer than wide, with its anterior margin con- 

 cealed and its lateral and posterior very conspicuous, rounded towards the 

 posterior angles and emarginated behind ; the sides slope and form a rectangle, 

 and the surface is filled with deep oblong pits. 



The anal fin is situated midways between, or scarcely in advance of, the cen- 

 tral point between the bases of the pectoral and caudal fins ; it is oblong and 

 equals or nearly equals the width of the head. The pectoral filaments extend 

 about to the middle of the anal fin ; the ventrals are inserted midways between 

 the lower jaw and base of caudal, and extend backwards to the anus, entering 

 2| times in the head's length. 



D. I. 7. A. 27. C. 13. 1. 7. 6. T. 12. P. I. 13. V. 6. 



The color above is plumbeous ; the pectorals thickly dotted with black on 

 their inner faces ; and the anal less so. 



One specimen eight inches long is in the collection. 



Family LEP ID OSTEOID JE. 



Genus ATRACTOSTEUS Girard ex Raf. 

 Atractosteus tropicus Gill. 

 The height is contained 8 J times in the extreme length, and i3 nearly a half 



[June, 



