296 PROCEEDINGS OP THE ACADEMY OF 



Length of disc 17 in.; of head and neck 19 in. 6 lin.; total, four feet. Length 

 of sternum 20 in. 6 lin. 



Habitat. The Rembo and Ovenga rivers, tributaries of the Fernando Vas, 

 Equatorial West Africa. 



Not having at hand specimens of the Aspidonectes niloticus of W. and S. 

 Africa, we have been unable to compare the only specimen of the aspilu s with 

 it; their differences are, however, sufficiently obvious. In the latter the sternal 

 callosities are much smaller, and the anterior pair have their anterior and 

 posterior borders nearly parallel, and the outline of the inner semicircular. 

 The tail is shorter, and the colors are brownish green with white and yellow 

 spots. 



The Old World Aspidonectes possess eight pairs of ribs ; we do not 

 know how it is with the American species, as there are no authentic specimens 

 in the Acad, mus., but our Amyda and Glatypeltis have but 7 pairs. 



EMYDOSAURIA. 



Crocodilus marginatus Geoffr. Brought by Mr. Duchaillu, from the 

 Ogobai. This species is principally abundant in the Cape colony, but is found 

 in other parts of Africa. 



OPHIDIA. 



COL UBRIDJECALAMARINJE. 



Omsthenes nob. 

 Head scarcely distinct from the body, depressed, especially in front. Muzzle 

 elliptical in outline, projecting much beyond the under jaw, as does also the 

 superior labial region. At the posterior extremity of the superior maxillary 

 bone are two curved teeth, larger than the other maxillaries, separated from 

 them by an edentulous space, and grooved in front. Cephalic shields normal. 

 Vertical broad ; loral small. Rostral prominent, broad, dividing the anterior 

 frontals somewhat ; not recurved. Preocular 1, postoculars 2. Urosteges and 

 anal shield entire. Scales very smooth. 



0. euphaeus nob. Scales subequally hexagonal on the flanks, more elon- 

 gate on the back, very little imbricate ; in nineteen rows. The rows diminish in 

 number upon the tail, by two or more running together upon the dorsal region, 

 thus forming short series of from four to six scales twice or thrice the usual 

 width. Vertical plate broad, hexagonal, the anterior angle very obtuse, the 

 posterior acute, dividing the occipitals. Superciliaries rather small, broader 

 behind in consequence of the convergence of the sides of the vertical. Posterior 

 frontals large, extending on the side of the head halfway along the preocular. 

 Anterior frontals rather small. Nostril between two nasals ; the anterior large, 

 separating the rostral and first labial, and nearly reaching the edge of the 

 mouth. Rostral broad, triangular, depressed, slightly dividing the anterior 

 frontals. Postoculars two. Superior labials eight, the first three small, the 

 eye resting on the fourth and fifth. Pupil erect, elliptical. Inferior labials 

 eight, the fourth largest, and in contact with the posterior geneials, of which 

 there are two pairs. 



Gastrosteges 205, anal 1, urosteges 75. 



Color uniform brown, dark on the head and anterior part of the body, lighter 

 posteriorly, and pale beneath. 



Length 2 ft. 9 in. 6 lin. Tail 17 in. 6 lin. 



Had Dr. Guntber placed his Hologerrhum philippinum among the Calama- 

 rinae, instead ofScytalian Colubridae, we should have felt well satisfied in re- 

 cording this as a second species of that genus ; we are not positive, indeed, that it 

 may not yet be so considered ; but with our present knowledge we must distin- 

 guish it generically. The head of this serpent is very Calamarian in its indistinct- 

 ness from the body, its depression and projecting rostral. Besides these, a broader 

 vertical and more distinctly divided rostrals distinguish it from Hologerrhum. 



[Nov. 



