SPERMATHECA. 121 



probably two of these belong to a fascicle which has 

 lost the other two by the accidents of dissection. I 

 thus should group the organ as composed of two 

 fascicles, each containing four branches. If Prof. 

 Huxley's figure relating to Vacuna should be accepted 

 as really applying to Callipterus, this would entirely 

 agree with his description of the same. 



The colleterial glands of Callipterus are very obvious. 

 They appear as somewhat pear-shaped bodies, deflected 

 at their summits, and narrowing at their bases so as 

 to form a kind of blunt hook. They discharge the 

 mucus-like secretion they elaborate into the vagina, by 

 a duct situated close to the vulva. 



These glandular pouches have very dense walls, 

 which are much corrugated within. The supposition 

 that their office is to form a shell to the egg before its 

 exit would seem to be untenable, because similar 

 organs are to be found in the larval females. As the 

 young Aphides at birth are well lubricated, this 

 mucous covering may be furnished by the glands in 

 question. 



The spermatheca is not easily separated from the 

 other organs. It occurs in Callipterus as a blind 

 pyriform ocecum, the mouth of which opens into the 

 vagina above the colleterial glands. Its coat is plenti- 

 fully supplied with muscular fibre. From the interior 

 of a specimen I examined, an immense number of 

 spermatozoa were expressed, and these disseminated 

 themselves into the weak glycerine used during dissec- 

 tion. I could not say that they showed no independent 

 motion, but what motion there was, consisted appa- 

 rently of a feeble movement, almost " Brownian." 



It has been before noted that the number of ovi- 

 gerous tubes which form a fascicle, and the number of 

 the ovarian capsules, vary in separate genera ; but we 

 cannot yet state how far this numerical variation is a 

 constant factor. In Aphides low in the scale of 

 development we have seen that a single egg only 

 cornea to maturity, the other germs atrophy, or 



