and their Anatomical peculiarities. 329 



Sect. III. The Sternoptix Celebes. 



The peculiarities of this fish, serving to distinguish it from the S. Her- 

 mannii, the other species of the same genus, I shall next enumerate. 



Locality. The Sternoptix Celebes was caught by my friend Mr Thomas 

 Kincaid, surgeon R.N. in September 1836, in the Straits of Macassar, 1° S. 

 lat. and 119° E. long., and within thirty miles of the Celebes coast, during 

 calm and clear weather. It was first observed swimming on the surface 

 of the water, apparently disabled from a deep cut it had received upon 

 the back. It is uncertain whether it frequents shoal or deep water, but 

 some fish resembling it were observed swimming about the roots of trees 

 which had been washed from the coast by the rains, and which trees tlie 

 fish seemed to have accompanied from the coral reefs near the shore. 



Size. The length of the specimen which I possess,* which appears to 

 have reached full maturity, is, exclusive of the tail, two inches and a 

 quarter, its height is two inches, its greatest thickness scarcely half an 

 inch. 



Form of Chest. On each side of the carinate and pellucid lower bor- 

 der of the chest, is a series of small fovese or dimples, eight in number.t 

 There is no sternum or osseous basis supporting these pits, but simply 

 minute fibro-cartilaginous expansions which project from the extremities 

 of the ribs, and unite with each other at the mesial line. Accordingly, 

 the interspaces between these being muscular, there may hence ensue, 

 during the relaxed state of that texture, the regular depressed appearance 

 referred to. 



The Caudal Region, which runs one-half of the length of the body, is 

 convex and carinate below, and the posterior and lower triangular por- 

 tion of this cavity is, from the vertebral spines downwards, resolved 

 into a pellucid membrane. + This membrane, which consists of two 

 layers of tegumentary texture, is sustained in a tense and vibratory con- 

 dition anteriorly by four slender bony processes, which arise from the 

 posterior margin of the anal interspinal bone (a bone which forms truly 

 the posterior boundary of the abdomen), and after traversing the space 

 between the laminae of the pellucid membrane in which they radiate, in 

 a direction obliquely downwards and backwards, serve finally to sustain 

 the anterior rays of the anal fin. Posteriorly, this membrane is stretched 

 upon the five last interspinal osseous spiculse, which, in their turn, sup- 

 port the middle rays of the anal fin.§ 



Head. The ridge of the principal frontal and interparietal bones is 

 distinctly dentated. There are also similar dentations on the inferior 

 margin of the sub-orbital bone. 



* See Plate III. I am indebted for the very faithful and accurate delineations of the 

 anatomy of the S. Celebes which illustrate this paper, to my estimable friend and laie pupil, 

 Mr Willington, surgeon at Saltisford, Warwick. 



tibid. I See Plates in. and IV. figs. 1. § Plate IV. fij? 1. 



