NATURAL SCIENCES OF PHILADELPHIA. 149 



ocellus on the anterior half of the soft part of the dorsal fin, which also advances 

 downwards as far as the lateral line. The color of the body, below the late- 

 ral line, is yellowish brown, with an indistinct dot on each scale; the caudal, 

 pectoral, ventral and anal fins as well as the dorsal fin behind are also yellow- 

 ish, the external ventral ray and margin of the anal before being darker. 



One specimen, about three inches long, was discovered at Cape St. Lucas by 

 Mr. Xantus and sent to the Smithsonian Institution. 



POMACENTRDS BaIRDII Gill. 



This species has the hinder and lower part of its length colored like the pre- 

 ceding, but there is no trace of an ocellus, and the base of the soft part of 

 the dorsal is blue. The ventral fins are also very light. The blue lines from 

 the snout end over the pupils ; a transverse line, a third of the interorbital area, 

 exists on that area, and behind it are two short parallel longitudinal lines. 

 There are three blue spots on the suborbital chain and one behind the angle of 

 the mouth. The scales below are not dotted with blue in the middle. 



Two specimens, rather less than an inch long, are in the collection of the 

 Smithsonian Institution. The preopercular serrature is almost obsolete. 



POMACENTRDS QUADRIGUTTA Gill. 



The present species differs from P. rectifrcenum by the greater portion of each 

 scale being blue ; the presence of two distant blue spots on the back, one be- 

 low the end of the dorsal fin, and another at the end of the base of the anal ; 

 the color of the head above more like that of P. Bairdii. The ventrals are dark 

 as in P. rectifrcenum, edged, like the anal, with blue. 



Many specimens, less than an inch long, were obtained and sent by Mr. Xantus 

 to the Smithsonian Institution. The preopercular serrature is very faint. 



Genus CHROMIS Guv. 



Furcaria was established by M. Poey for two species of Pomacentroids 

 found along the Cuban coast, which were supposed to be distinguished from 

 all others by seven branchiostegal rays aod the unequal teeth. M. Poey has 

 kindly sent to the Smithsonian Institution two specimens of the type of his 

 genus, the Furcaria puncta, and, after a careful examination but without dis- 

 section, I have been unable to count a number so unprecedented and remark- 

 able for a Pomacentroid, and have only discovered five. The name might, how- 

 ever, be retained for the group which differs from the typical species of Chromis 

 or Heliases by the presence of only twelve dorsal spines.* 



Chromis (Furcaria) atrilobata Gill. 



The form is probably nearly similar to that of Furcaria puncta, but the only 

 specimen sent to the Smithsonian Institution by Mr. Xantus is much injured 

 and shrivelled up, although preserved in alcohol. The greatest height is esti- 



* Another type of the Pomacentroids characterized by a band of conical teeth in each 

 jaw is Dascyllus Cuv. {Tetrad rachmum Cantor). An elegant undescribed species is found 

 at the Sandwich Islands, from which specimens were sent to the Smithsonian lnstiuition 

 by Mr. W. H. Pease. It may be called Dascyllus albixella ; it has the form of Daxcyllus 

 marginatus Ehr. ; its height exceeds half the entire length. The head forms nearly a 

 quarter of the same. Its forehead before the eye is vertical. The dorsal spine regu- 

 larly decreases from the second to the last, the second equalling the length of ihe head 

 and about twice as long as the last. The soft pans of the dorsal and anal are arched. 



D. XII. 16. A. II. 15. 

 5 2 



Scales 27, -. Lat. line 1819. 

 12 3 



The color is dark grayish, wilh a transverse white band descending half way down 

 from the middle of ihe back below the dorsal fin, between its fifth and tenth spines. All 

 the fins, except the pectorals, are very dark. 



1862.] 



