7. osi'iiuojrr.Ni's. 385 



3. Osphromenus siamensis. 



D.|. A.ii^iJ. L. lat. -L2. L. transv. 12/16. 



The height of the body is one-half of the total length (the caudal 

 fin not included). 



Fresh waters of Siam. 



a-e. Fine specimens. From M. Mouhot's C'oUection. 



Description. — When we take the origin of the dorsal fin as the 

 highest point of the upper profile, and the base of the last dorsal 

 spine as the lowest of the abdomen, the depth between these two 

 points is one-half of the total length (the caudal not included). The 

 length of the head is three times and two-thirds in the same length. 

 The snout is broader than long, equal to the diameter of the eye, 

 which is one-fourth of the length of the head. The interorbital 

 space is convex, wider than the oi'bit. Mouth very small, rather 

 protractile ; praeorbital with its extremity truncated and serrated ; 

 angle of the pra)operculum serrated ; there arc two or three series of 

 scales between the eye and the angle of the pra^operculum. The 

 dorsal fin commences nearer to the root of the caudal than to the 

 end of the snout ; it has six strong spines, which increase in length 

 posteriorly, the last being longer than one-half the length of the 

 head. Caudal emarginate ; the anal is nearly entirely scaly, and 

 terminates immediately before the caudal. The longest ventral ray 

 extends beyond the extremity of the caudal, and has three or four 

 rudimentary rays in its axil. 



The colour is greenish on the back, silvery on the sides and on the 

 belly. A black spot on the middle of the body in the vertical from 

 the origin of the dorsal, below the lateral line ; a second on the middle 

 of the root of the caudal. The soft dorsal and caudal with brown 

 dots ; anal yellowish, with lighter spots, and sometimes with brown- 

 ish dots. 



This description is taken from specimens v hich are from three to 

 four inches long. 



4. Osphromenus microlepis. 



D. ^. A. ^. L. lat. (50. J., transv. 12 22. 



The height of the body is one-half the total length (the caudal fin 

 not included). 



Fresh waters of Cambojia. 



a. Fine specimen. From M. Mouhot's Collection. 



Description of the specimen. — The height of the body is one-half 

 of the total length (without caudal), the length of the head two- 

 sevenths ; the profile of the nape is convex, that of the head rather con- 

 cave. The .snout is somewhat depressed, broader than long, with the 

 lower jaw prominent ; the interorbital «pace is convex, nearlj- t^ice 

 as wide as the orbit, the diameter of which is one-fifth of the length 

 of the head, and less than that of tlie snout. Pra?orbital triangular, 



VOL. III. 2 ( 



