Cha^topterns Varioppclatiis. 



513 



pellets of organic matter in the stomach and intestine. These pellets 

 consisted of small protozoa and other low animals that were abundant 

 in the diatom cultures to which the larvae were transferred. 



These larva? (Fig. 0) are more elongate, and while not very dif- 

 ferent in appearance from the underfed larvse, show some striking 

 differences. There are three pairs of eye-spots ; two pairs lateral 

 and one pair in an antero-dorsal position just back of the anterior 

 flagelkim which still persists. The additional eye-spot on each side 

 is smaller than, and directly in front of, the one mentioned for the 

 previous stages. (Some individuals had, besides, a row of two or 

 three smaller accessory pigment spots anterior to these.) The antero- 

 dorsal pair is seen through the transparent dorsal wall of the esoph- 



iagus. The second band of powerful cilia which, in the earlier stage, 

 was at the level of the middle of the intestine, is now relatively 

 farther forward as a result of the backward growth of the stomach 

 and elongation of the growing-region between the anus and second 

 circle of cilia. The circle of cilia is incomplete for a short space 

 on the ventral side as Wilson observed in larvse which he reared 

 from the eggs. 



The ventral margin of the hemispherical pre-oral lobe has begun 

 to be tilted forwards (anteriorly) so that the mouth now has a 

 greater axial as well as a greater transverse diameter. The free 

 margin of the cleft post-oral lol^e is thicker and is turned ventral- 

 wards. The esophagus, stomach and intestine have not changed 

 excepting in length. 



