APPENDIX. 493 



drawn up, and ichthyologists may consider Assiculus, either as a 

 proper generic form, or as merely a subgenus or subdivision of 

 Psendochromis, with an extended character, according to their 

 different views of arrangement. The last named genus, :is 

 described and restricted by Dr. Riippell, from whom all our 

 knowledge of it is derived, has the jaw teeth disposed in a 

 single row, and the minute palatine teeth of a sphaeroidal form. 

 The operculum has its angle prolonged, and is not toothed, 

 nor is the suboperculum crenated ; and a considerable number 

 of the rays of the dorsal fin, succeeding to the three spinous 

 ones, are simple but flexible, the posterior ones only being arti- 

 culated and divided in the usual manner. Linnaeus has briefly 

 characterized two fish, (Lahrus ferrugineus, Bl. Schn. p. 251, 

 and Lahi'us marginalts, Id. p. 263), which most probably 

 belong, either to Pseudochromis or Assiculus, and which are to 

 be placed, M. Valenciennes thinks, near Malacanthus, ainon^^ 

 the Labridce. Now, this family, according to M. Agassiz, is 

 essentially cycloid in the structure of its scales, although there 

 is a slight departure from the rigid characters of the order in 

 the serrated preopercular of Crenilahrus, Ctenolahrus, and some 

 others, and in the spine bearing operculum of Malacanthns. 

 The latter genus is, moreover, described by M. Agassiz as 

 possessing scales with toothed edges, and rough to the touch 

 when the finger is drawn forwards. It has the simple intes- 

 tinal canal without caeca, which is proper to the LabridcB. 

 The intestine of Pseudochromis is similarly formed, the 

 stomach being continuous with the rest of the alimentary 

 canal, and not distinguished by any ctil de sac. Having but 

 one specimen of Assicidus for examination, I have not been able 

 to submit it to dissection to see whether the structure of its 

 intestines be the same or not, but both it and Pseudochromis 

 differ very widely from the labroid type in their scales, pos- 

 sessing the peculiar firm, shining, strongly ciliated structure, 

 which we observe in Glt/phisodon and its allies, and in the lateral 

 line being interrupted in a precisely similar manner. Chromis 

 and Plesiops have already been removed by M. Valenciennes 

 VOL. I. *2 K 



