42 



BEKYCID^. 



1 7. Holocentrum diadema. 



Holocentrus diadema, Lucep. iv. pp. 372, 374, iii. pi. 32. f. 3; Rilm. 



All. Fisvh; p. 84. t. 22. f. 2. 

 Perca piilcliella, Bonn. Zool. Journ. iii. p. 377. pi. 9. f. 3. 

 Ilolocentruiii diadema, Cm: lij- Vul. iii. p. 213 ; Less. Voy. Duperr. 



Zool. ii. p. 220. pi. 25. f. 2 ; Blacker, Amhoina ii,- Ceram, p. 259. 



D. 11 1 f^. A.-|. L. lat. 48. L. transv. 3/7. Vert. 11/16. 



The height of the body is 3f in the total length, the length of 

 the head four times ; the interspace between the eyes is one-fifth of 

 the latter. Operculum wth two prominent spines, the upper of 

 which is the stronger, nearly equal in size to that of the praDopcrculum. 

 The fourth, fifth, and sixth dorsal spines longest, as high as the 

 longest ray, but shorter than the anal spine. The length of the 

 caudal is one-sixth of the total, both the lobes being equal. The 

 third anal spine is exceedingly strong, and about one-fifth of the 

 total length. The ventral fins reach near to the anus, but the 

 pectorals are much shorter, lied, ^dth eight to eleven silvery lon- 

 gitudinal bands ; the spinous dorsal black, with a wliite longitudinal 

 band ; the other fins rose-coloiu'ed. 



Red Sea ; Madagascar ; Ceylon ; Chinese Sea ; Indian Archi- 

 pelago. • 



a. Adult. Borneo. 



b. Half-grown. China Seas. Presented by Capt. Sir Edward 



Belcher. 



c. Half-grown. Tonga Islands. From the Haslar Collection. 



d. Half-grown. Feejce Islands. Voyage of the Herald. 



e. Half-grown : very bad skin. Ceylon. From the Collection of 



the Zoological Scfciety. 

 /. Adult. Madagascar. Presented by Dr. J. E. Gray, 

 r/. Adult : skeleton. India. From Mr. Frank's Collection. 

 h, i. Adult. India. From Mr. Frank's Collection. 



STceleton. — The general structure of the skeleton being the same 

 as in Holocentrum rubrum, I give a detailed description of those 

 parts only which exhibit specific peculiarities. 



The fan -like expansion on the vertex is formed by ten or more 

 radiating branches; the groove for the posterior processes of the inter- 

 maxillaries reaches a little beyond the level of the anterior margin of 

 the orbit. The maxillaiy and mandibulary bones as in H. vioJaceum. 

 The intermaxillaries arc not separated from one another by a notch ; 

 they are three-quarters of the length of the raaxiUaries, and have a 

 prominent flat protuberance posteriorly. 



The dentition is formed by viUiform bands only; those on the 

 jaws reach to the posterior extremity of the bones ; they are broad 

 in front and tapering behind, the intermaxillary band less than 

 that of the mandibulary. The vomerine teeth are placed in a small, 

 triangular, equilateral patch, those of the palatine bones in a narrow 

 band, extending on the pterygoid. The teeth of the pharyngo- 

 branchials form two broad patches on each side, with a few snudler 



