148 PROCEEDINGS OP THE ACADEMY OF 



The dorsal fin commences above the first scale of the lateral line; its greatest 

 height equals or exceeds a quarter of the length ( # 26), The caudal ha3 acute 

 lobes, forming more than a quarter (-27) of the length, while the median rays 

 scarcely equal a sixth (-16) of th'o same. The pectorals and ventrals are 

 nearly equally long and exceed a quarter (-21 -22) of the length ; the latter 

 are inserted immediately behind the former. The dorsal and anal are densely 

 scaly. 



3 2 



D. XII. 13. A. II. 11. Scales 26 . Lat. line 21. 



10 3 



The color of the entire fish is a deep purplish brown, relieved on the back by 

 two blue spots on each side, as in Pomacenlrus quadrigutta, (under the fourth spine 

 and under the third or fourth ray,) close behind the dorsal by a transverse 

 linear spot, and on or just above the first scale of the lateral line by another spot. 

 A blue line extends from the snout to the front of the orbit, and a spot exists 

 above before the middle of the orbit. Another blue line crosses the preorbital 

 and passes under the eye. There are also a few other blue dots scattered on 

 the head. 



A single specimen of this species, four inches long, was sent by Mr. Xantus 

 to the Smithsonian Institution. 



Genus POMACENTRUS Lac. 



POMACENTRUS RECTIFRiENUM Gill. 



The height equals a third (34) of the total length, inclusive of the entire 

 caudal. The head is regularly decurved from the nape and forms nearly a 

 quarter (23) of the total length ; its height at the preopercular margin ex- 

 ceeds the length (-24) and is rarely a quarter greater than that of the pupil 

 (19). The length of the snout exceeds a third (-8) of the head's, is greater 

 than the diameter of the eye (-7), which itself is more than twice as great as 

 the height of the entire preorbital (-3) at the angle of the mouth. The pre- 

 operculum is finely dentated and vertical behind. The teeth are entire. 



The dorsal commences above the upper axilla of the pectoral ; the greatest 

 height exceeds a fifth (21) of the total length, and equals the length of the 

 pectoral (21). The ventrals are inserted behind the pectorals, and equal a 

 quarter of the length. The caudal forms about a quarter of the extreme length, 

 and the inner rays exceed a sixth (-16) of the same. 



3 2 



D. XII. 16. A. II. 15. Scales 25--. Lat. line 21. 



10 3 



The color is a deep chestnut, dotted with light blue on each scale on the back 

 and tail, and on the sides with a faint crescentiform line, parallel with the 

 border of each scale. The head has two blue lines diverging from the snout 

 and passing over the eyes to each side of the dorsal ; there is an oblique one 

 on the preorbital and also a suborbital line, as well as one below the suborbital 

 chain. Another proceeds backwards from the upper angle of the orbit. A 

 black spot, bordered by blue, is more or less developed behind the dorsal. The 

 dorsal, anal and pectoral are very dark, and the first two dotted with blue. 



There are six specimens in the collection of the Smithsonian Institution. The 

 pattern is similar, but not equally vivid in all. There is no indication of a dor- 

 sal ocellus. 



The following two species were at first supposed to be varieties of one spe- 

 cies of romacentrus, but, as there are no gradations, and as they differ slightly 

 in pattern of coloration as well as the presence of a dorsal ocellus, it is impro- 

 bable that such is the case. 



POMACENTRUS FLAVILATUS Gill. 



This species differs from the preceding by the presence of a very distinct 



[March. 



