2 68 JOHANNA M. DIECKMANN. 



It should be noted that the cellular area ot the 10.3 and 10.5 

 cm. animals lies in the same relation to the two groups of glands 

 and to the median dorsal fold, as does the spermatheca in the 

 10.8 cm. animal namely, the ventral glands and the dorsal 

 fold are more cephalad, and the dorsal glands are more caudad. 

 This gives additional ground for interpreting the cellular area 

 as the anlage of the spermatheca. 



In the next stage (10.7 cm.) the whole organ has enlarged; 

 the tubules which still spray both cephalad and laterad, are 

 longer and more isolated from each other, and have definite 

 lumina. Again the common tube is of interest; in its caudal 

 portion its lumen is shaped like a short-stemmed Y, and has an 

 epithelium three cells deep (Fig. 20); cephalad, however, the 

 common tube is not branched, and several irregular lumina 

 appear in the midst of the mass of cells from which the tubules 

 spring, as though the common tube were enlarging by degenera- 

 tion or pulling apart of epithelial cells as the tubules acquire 

 lumina. Ventral glands are more numerous and open well up 

 on the lateral walls of the cloaca. No dorsal glands are present 

 in this animal. 



A further development in an animal of approximately n.o cm. 

 (tail partly broken off), is seen in the elongation and change of 

 direction of the tubules; most of them stream conspicuously in 

 a caudal direction and then curve ventrad (Fig. 22); others 

 spray cephalo-laterad ; while those most cephalic in position, 

 point almost directly dorsad. In the adult there are no tubules 

 pointing cephalo-laterad or dorsad; these have all been turned 

 more caudad. In the n.o cm. animal the limbs of the Y-shaped 

 portion of the common tube seem to be increasing in height by 

 degeneration of epithelial cells where tubules spray out from 

 the limbs of the Y (Fig. 23). 



In the three animals just described (10.8, 10.7, and n.o cm.) 

 the cloaca showed progressive increase in number and size of its 

 folds, especially in the height and breadth of the pair lying one 

 on each side of the median dorsal slit. These were first indicated 

 by a slight notching in the lateral walls of the cloaca at the 

 "cellular area" stage (Fig. 16), but developed rapidly (Figs. 18 

 and 20). This pair will subsequently become the caudal two 



