652 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



OIV the: I>IFE COIiORATIOIV OF THE YOUIVG OF POMACEIVTKU8 

 RUBICUIVDIJS. 



By ROSA SMITH. 



Hitherto only the adult form of this species has been known, and its 

 uniform deep scarlet coloration has been considered to form a marked 

 contrast to the coloration of the other species of Pomacentrus. I have 

 lately secured numerous young specimens, and find their coloration quite 

 different from that of the adult, and in general similar to that of the 

 other members of this genus. 



The ground color is dusky scarlet, with numerous markings of an in- 

 tensely bright blue, which occasionally changes to bluish green. Two 

 series of elongate spots form a blue stripe on either side of the median 

 line, between tip of snout and beginning of dorsal fin; a line of blue 

 on superior margin of iris is followed jiosteriorly by an irregular 

 series of blue spots above the lateral line (the individual spots not 

 quite equaling diameter of iris); the last of these spots is larger than 

 those which precede it, being two-thirds of the orbital diameter, and 

 extends up on the base of the dorsal fin at the posterior third of the 

 spinous portion ; thence very small blue dots continue to the end of the 

 dorsal fin, describing a curve which exactly outlines the extent to which 

 scales cover the base of the articulate dorsal rays; a conspicuous blue 

 spot or bar crosses top of caudal peduncle close to posterior insertion 

 of dorsal fin. One or more small blue spots at base of caudal. The 

 spine and first ray of ventral blue ; spines and tips of anterior rays of 

 anal blue; a nearly round blue spot on posterior part of anal near its 

 base. Sides of body more or less dotted with blue, as are also the 

 cheeks and opercles. Pectorals and caudal semi-transparent, plain red- 

 dish. Ground color of anal bright red. Dorsal fin dusky, with minute 

 blue dots anterior to the markings mentioned. Abdomen and under sur- 

 face of head lighter, immaculate. 



This description is made from specimens 1| to 2 inches in length. 

 Specimens less than 1 inch long have the spinous dorsal almost wholly 

 blue and all the markings larger, while an individual 3h inches long 

 shows the markings similarly placed but relatively smaller, and tbe 

 ground color is more olivaceous. 



The fin-rays are proportionately higher and the eye relatively larger 

 than in the adult. The suborbital and jireopercle are without serra- 

 tions. The small opercular spine, unlike that of the mature form, is 

 smooth and wholly without denticulations. The greatest depth of the 

 body is about half the length. 



