NATURAL SCIENCES OP PHILADELPHIA. 259 



with eight filamentous spines, and the pectoral fin elongated, it would resemble 

 a Nematibiim. 



The peculiar modification of the ventral fins reminds the naturalist of the 

 genus Lampris, the type of a peculiar family, but in other respects it is little 

 related. On account of this modification of the ventral fins, as well as the 

 development of the dorsal fins and the form, it appears expedient to consider 

 it as the type of a distinct family, allied to the Carangoids and Coryphaenoids. 



Nematistius pectoralis Gill. 



The greatest height equals or exceeds a quarter of the length from the snout 

 to the end of the median caudal rays. The head nearly equals the height, and the 

 height at the nape is not much less (-22 -24.) The direct distance between 

 the orbits equals a third of the head's length ; the orbit has a diameter equal 

 to a fourth of the same length, is distant from the horizon of the forehead half 

 a diameter, and from that of the snout little more than a diameter. The height 

 of the suborbital bone equals a third of the diameter. The origin of the anal 

 fin is nearly equidistant from the throat and the end of the caudal. The pec- 

 toral equals about three-tenths of the length and is nearly twice as long as the 

 ventrals. The median rays of the caudal fin equal the length of the snout and 

 quarter that of the longest. 



D. VIII. I. 26. A. I. 15. P. I. 1. 14. V. I. 54. 



The color of a dried specimen is plumbeous on the back and operculum, and 

 silvery on the sides of the head as well as body. The dorsal filaments are 

 black ; the lower half of the pectoral fin is also blackish. 



The following table of measurements is taken from the dried specimen, the 

 only one obtained. It has been registered as No. 2421. 



Length from snout to end of median caudal rays (16 inches) 100. Body 

 greatest height 26. Height behind dorsal and anal -09. Height of caudal pe- 

 duncle -06. Length of caudal peduncle "11. 



Head Length laterally 24. Height at nape 22. Width between orbits 8^. 

 Length of snout 6^. Height of suborbital bone 2. 



Eye Diameter 6. Distance from profile 3. 



Dorsal (spinous) Length of first spine 6^. Length of second spine 31. 

 Length of third spine 55. Length of fourth spine 53. Length of fifth spine 52. 

 Length of sixth spine 41. Length of seventh spine 36. Length of eighth 

 spine 43. 



Caudal Length of median rays 6J. Length of longest rays 25. 



Pectoral Length 31. 



Ventral Length 16. 



Family CIRRHITOIDJE (Gray.) 

 * Subfamily CIRRHITIN^E (Blkr.) Gill. 



Genus Cirrhitus Lac. 



ClRRHITUS RIVULATUS Val. 



Voyage de la Venus, Zoologie, p. 309, pi. 3. fig. 1. Giinther, Catalogue of the 

 Acanthopterygian Fishes, &c, vol. ii. p. 519. Gill, Proc. Academy of 

 Nat. Sciences of Phila., &c, vol. xiv. 1862, p. 107. 



A single stuffed specimen, fifteen inches long, was sent to the Institution by 

 Mr. Xantus. 



Cirrhitus betaurus Gill. 

 The greatest height exceeds a quarter (-27) of the extreme length, and the 

 head forms nearly a third (-32) of the same. The preoperculum is serrated 

 behind. In the small specimen now described, the diameter of the orbit is * 

 contained little more than three times and a half in the head's length and 

 equals the snout. The fourth dorsal spine is longest, and equals a ninth of 



1862.] 



