Hermaphroditism among the Apodidte. 303 



ripe, it is difficult to see why the eggs should not be fertilized 

 by the sperm-cells. The only hindrance would be the coating 

 of slime. There is no reason to believe that this, which in 

 the living state would be quite soft, would be sufficient to 

 prevent one or more sperm-cells from finding their way into 

 the egg. They may perhaps be mechanically squeezed 

 through the slimy covering in the process of stretching the 

 duct on their passage to the egg-pouch. 



Fig. 9 shows two tubules lying across one another, in both 

 of which a portion of the epithelium has broken down into 

 sperm-cells. One of these alone need engage our attention. 

 An egg, which has all the appearance of degenerating, occurs 

 at the tip, while the epithelium of the neck of the tubule 

 which carries the egg has broken up into sperm-cells and 

 slime. On one side the proliferation of the cells has caused 

 the neck to bulge out greatly. 



Figure 10 shows the same phenomenon. A couple of eggs 

 developing at the tip of a tubule dorsally in the region of 

 the fourth leg or ninth appendage appear to be rapidly degene- 

 rating. On the other hand, the neck of the stalk-like tubule 

 is swelling up (from a to b) by the rapid division of the epi- 

 thelial cells into masses of sperm-cells. 



In the foregoing, in order to avoid needless circumlocution, 

 it has been assumed that these minute cells are sperm-cells. 

 The question, then, is — Are they or are they not? The 

 evidence here adduced leaves little doubt that they are. 

 Until, therefore, it is shown, by direct comparison with the 

 undoubted sperm-cells of a male, that they do not resemble 

 such cells in any way, differing entirely in size, shape *, and 

 mode of origin as far as the last has here been sketched, it 

 seems to me that we are justified in asserting that the 

 Apodidse are hermaphrodite under certain conditions of exist- 

 ence. 



Before endeavouring to ascertain what the necessary con- 

 ditions are which lead to this hermaphroditism, one point 

 raised by Dr. Benham's paper calls for brief comment. He 

 speaks of hermaphroditism in Apus as improbable. Nearly 

 all who have worked comparatively at ovigenesis or spermato- 

 genesis have emphasized the already admitted fact that both 

 ova and sperm develop from the same elements, and that the 



* Very little can be made out of Kozubowski's figures and account 

 (Arch. f\ Naturg. xxiii.) of the sperin-cells of a male Apus. It is very 

 doubtful whether he saw the ultimate sperm-cells. His figures show 

 what appear to be spherical packets of cells resembling somewhat those 

 found in the sperm-forming centres uf the hermaphrodite specimens. 



