1021.] vS. L. HORA : Fishes oj the genus Garra. 641 



rior lip {h) is a narrow groove which separat^^s it from the fold (g) 

 covering the tip of the snout. Both the li]is are continuous near 

 the angle of the mouth. The anterior lip is of almost uniform 

 thickness throughout and is partially covered by a flap of the 

 posterior lip (/) near the angle of the mouth. The posterior lip 

 can be divided for description into tliree parts, the median narrow 

 part (h) and the two swollen bulb-like lateral portions (/). The 

 bony elements of the jaws are not visible. There are two pairs 

 of short barbels and the eyes are distinctly visible from below. 

 There is as yet no indication of the disc and the branchiostegal 

 membranes which meet at an acute angle are continued forwards 

 for a considerable distance. 



A slightl5' more advanced stage is shown in figure 2, the only 

 noteworthy feature being the presence of an almost circular area 

 (represented by dotting in fig. 2) immediateh' behind the posterior 

 lip. This area I consider to be the rudiment of the disc organ. 



In stage 3 the disc rudiment (/) is restricted and is repre- 

 sented by a few papillate concentric lines, the squarish area 

 between these and the posterior lip may now be called the disc 

 proper [e). At this stage the branchiostegal membranes are slightly 

 separated and the branchial isthmus has become wide. 



A marked change is shown in stage 4. The disc rudiment is 

 now represented by a transverse line of papillae (/) just behind 

 the disc proper (e) ; the anterior portion of the latter is indistinct- 

 ly demarcated as a somewhat prominent lolje which ultimately 

 develops into the posterior labial fold (c). Changes have also 

 taken place in the lateral bulb-like portions of the posterior lip (/). 

 A small area on each side is separated off just at the angle of the 

 mouth and is represented in the figure as a connective (d) between 

 the anterior and the posterior lips. The branchial isthmus is 

 still further widened and the branchiostegal rays are slightly re- 

 duced with their membranes somewhat separated. By a careful 

 comparison of the four stages it can readily be seen that the 

 mouth has shifted backwards and that the anterior labial fold is 

 coming into prominence. 



Between the fourth and the fifth stage there is a lack of 

 continuity. The disc rudiment is entirely absent and the anterior 

 labial fold is more extensive ; it has almost covered the anterior 

 lip (h), of which only the median portion is visible. The mouth 

 opening has shifted still further backwards aiid the disc is well 

 marked with lunate anterior (c) and semicircular posterior {/;/) 

 borders. In the development of the branchial isthmus, the 

 branchiostegal membranes and rays and the posterior lip, the 

 specimen from which this stage is described is less advanced than 

 that shown in stage 4. The connectives have not yet been separ- 

 ated, though near the angle of the mouth the lip is greatly 

 swollen. 



In stage 6 the features of the disc and the anterior labial 

 fold (c) are well pronounced, and the connective {d) is a distinct 

 structure. Changes have also taken place in the posterior lip and 



