I9I9-J T. SouTHWEr.L & B. Prashad : Studies of Indian Fishes. 221 



developed. The e3'e has become still more , enclosed in tlie 

 capsule. In the skull, the jaws are already nearly complete, 

 the enveloping bones and the teeth are beginning to be laid down. 

 In the vertebral column the body of the vertebrae, the neural and 

 the haemal arches are formed in the anterior part of the body 

 region but not further in the region adjoining the tail. So far 

 as the fins are concerned, this is the first stage in which the fin- 

 ra.ys have begun to make their appearance in the region of the 

 dorsal fin, though the basal pterygiophores could be distinguished 

 in this situation even in the last stage. In the anal and the caudal 

 fins the rays are already quite well developed and the limit between 

 these two fins is also just indicated by the direction of the fin- 

 rays. The. alimentary canal, the liver, and the air-bladder are 

 better developed. In the gills, the filaments are larger and are 

 present on all the four gill-arches. 



Stage VII (fig. 10). — This is the most advanced stage in 

 the collection and shows no trace of an external yolk sac. The 

 general colour is milky white in the preserved state. Irregularly 

 scattered chromatophores of the usual shape and of a brownish 

 colour are present on the head and on the abdominal portion ; 

 none, however, can be distinguished in the tail region. No scales 

 are developed as yet, but in sections of a portion of the body-wall, 

 scales can be distinctly seen developing in the scale-sacs. There is 

 still a continuous fin-fold, in which the dorsal fin is distinctly 

 marked off about the middle of the animal, and it has well devel- 

 oped fin rays. The thin covering of the fins is still directly in 

 continuation of the original dorso-ventral fin, which latter has 

 become greatly reduced posterior to the dorsal fin but is fairly 

 broad anteriorly. The pectoral fins are much larger and have 

 full}^ developed fin-rays. The yolk-sac is entirely withdrawn into 

 the body-cavity and is not visible externally. Unfortunately, the 

 condition of the material at our disposal does not allow of a des- 

 cription of the internal yolk sac, as the structure may now be 

 termed. The operculum is quite well developed, its posterior 

 boundar}^ lies a little behind the middle of the distance between 

 the snout and the anus. In the operculum, the opercular, pre-, 

 inter- and sub-opercular elements are marked off, and ossification 

 has commenced. Five branchiostegal rays are already formed 

 and traces of three others can also be seen , The anus lies at a 

 distance of about one-third the total length from the anterior end. 

 The eye is contained about four times in the head length and 

 its distance from the snout is equal to its diameter. The external 

 narial opening, which is seen as a distinct aperture in this stage, is 

 situated near the middle of the distance between the eye and the 

 snout. In the skull region also, ossification has commenced, but 

 the stage is too young to show the various elements. All the jaw- 

 bones are, however, well developed and teeth are present on the 

 maxillaries, dentaries, vomers and palatines. A few can also be 

 seen on the urohyals. 



In the l)ody. the irregular myosepta are to be distinguished 



