44. APOGON. 231 



c-e. Adult. Mediterranean. From Mr. Frank's Collection. 



/, Adult. Sicily. Presented by W. Swainson, Esq. 



g. Adult : bad state. Madeira. From the Haslar Collection. 



Skeleton, — The skull of the species of the genus Apogon is distin- 

 guished by the hemispherical prominent capsula cerebri, formed by 

 the parietal and occipital bones and by the hinder part of the 

 frontals ; the latter part is generally provided with two or more small 

 spinous prominences; the orbital part of the frontals is very de- 

 veloped, not flat, but "wdth a deep narrow groove along the median 

 line ; this groove is bifid behind, thus separating the orbital part of 

 the frontals from the posterior. In front of the median groove is a 

 high ridge, generally half as long as the diameter of the eye, and 

 bifid behind ; this ridge, together with those spinous prominences of 

 the frontals, is for the purpose of keeping the skin suspended above 

 the grooves. Large mucose cavities are formed thereby, commu- 

 nicating with those of the suborbital arch, &c. The occipital crest 

 is very developed and broad, more or less truncated behind, reaching 

 downwards to the vertebral column, and supported by another, 

 narrower, horizontal one, which arises also from the occipital. 

 Another peculiarity of the skull of Apogon is the internal free 

 ridge of the prseoperculum, parallel to the external margin. The 

 operculum is always supported by a strong, straight bony ridge, con- 

 spicuous from the outside, but prominent only at the inner surface ; 

 it arises near the articulation of the operculum with the epitympanic 

 (os temporale), and projects sometimes in a small free spine at the 

 hinder angle of the operculum. 



In Apogon imberbis the lower outer margin only of the proeoper- 

 culum is very finely denticulated, the teeth becoming smaller at the 

 angle. The vomerine and palatine teeth are arranged in a single 

 row, the series of the former forming a right angle. There are elevep. 

 abdominal and fourteen caudal vertebrae. 



2. Apogon heptastigma. 



Apogon heptastigma, {Ehrenherg) Cuv.-^ VaL ii. p. 160. 



Two black spots on each side of the tail ; brownish red, tins red- 

 dish ; five black spots at the base of dorsalis. 

 Red Sea. 



3. Apogon hyalosoma. 



Apogon thermalis, Blecker, Perc. p. 27 (not Cuv.). 



hyalosoma, Sleeker, Singapore, p. 63, and Amboyna, iv. p. 329. 



Caudalis slightly notched. Uniform yellowish, wdth a black spot 

 at the root of the caudal fin ; interspace between the second and third 

 dorsal spines black. Suprascapula, sub- and interoperculum entu'e ; 

 the upper maxillary bone reaching to below the posterior half of 

 the eye. 



Seas of Batavia, Sumbawa, Amboyna, and Sumatra. 



a. Adult. Amboyna. From Mr. Frank's Collection. 



