1853.] 369 



arches four on each side. Branchiostegal rays six in number, three on either 

 side. Scales varying in size according to the regions; small and not imbricated 

 on the back, large and imbricated on the flanks, and of medium size on the belly 

 and tail. Lateral line well marked, forming an open curve on the abdomen and 

 straight on the tail. Caudal fin forked or crescentic, generally unicolor ; the 

 tints of the back, flanks and abdomen merely varying in intensity. 



1. Gila roeusta, B. and G. Body very much swollen anteriorly, and taper- 

 ing very suddenly from the dorsal fin to the insertion of the caudal. Head very 

 much depressed above, sloping very rapidly from the nape to the snout, and 

 forming one fourth of the entire length. Eyes proportionally small and subcir- 

 cular. Mouth tolerably large ; the posterior branch of the maxillary does not 

 reach the vertical line of the pupil. Dorsal fin situated on the middle of the 

 back, and a little higher than long. Caudal crescentic. Anal situated behind 

 the dorsal. Insertion of ventrals in advance of the anterior margin of the dorsal. 

 The posterior tip of the pectorals does not reach the insertion of the ventrals. 

 All the soft rays are bifurcated. Lateral line composed of about ninety scales. 

 Color greyish brown above, lighter beneath. 



Formula of the fins : D I. 9. C 8. L 8. 8. T. 7. A L 9. V I. 9. P 'i5. 



2. Gila elegans, B. and G. Closely allied to the preceding species. Its 

 body, however, is more slender, and its tail proportionally more elongatad. The 

 caudal fin is more deeply emarginate and more developed, as indeed are all the 

 fins. The head is very much depressed and flattened on the snout. Eyes ellip- 

 tical. The scales are proportionally more elongated than in the preceding spe- 

 cies and are broader anteriorly than posteriorly; the lateral line has about 

 ninety of thpm. The number of rays in the fins affords also a distinctive mark 

 between both species. The ventrals have no rudiment of spiny ray. Color 

 liiiht brown. 



Fin rays : D III. 9. C 9. I. 9. 9. I. 10. A III. 10. V 9. P IG. 



3. Gila gracilis, B. and G. This specif^s is proportionally shorter, deeper, 

 and more compressed than its congeners. It reminds us, in shape and general 

 appearance, of the " Shiner " (Lenciscus america.Jius). Both the dorsal and anal 

 fins are provided anteriorly, as in G. elegans, with three rudimt^ntary spiny rays. 

 The scales are rather small, very thin: there are from SO to 90 of them in the 

 lateral line. The relative position of the fins is the same as in the other species 

 of this genus. Color yellowish brown. 



Fin rays : D III. 8. C 8. I. 11. T. 7. A III. 8. V I. 8. P IG. 



The Comniittee on Mr. Cassin's " Catalogtie of the Hirundinidae in 

 the Collection of the Academy," reported in favor of publication in the 

 Proceedinss. (0:^ See end of this Number.) 



The Committee on Mr. Cassin's descriptions of new Swallows and 

 Parrots in the Collection of the Academy, reported in favor of publi- 

 cation. 



Descriptiovs of tipiv species of llirinidlnidcp. and Psittacidce, specimens of which 

 are iu the collection of the Academy uf Natural Sciences of Philadelphia* 



By John Ca'=sin. 



I. HIRUNDINID.E. 



1. CyPSEL'.'S SQr^AMATUS, ?-'o5^.5. 



Form. About the size and general form of C amhrosincus and C. parvus. 

 Bill rather broad at base, curved, wings and tail long, the latter forked, toes and 

 claws strong. 



Dimensions. Total length (of skin) from tip of bill to end of tail about 5 

 inches, wing 4], tail 3 inches. 



Colors. Entire plumage of upper parts greenish black with a slight greenish 



