454 E. A. MINCHIN ON SOME DETAILS IN THE ANATOMY OF 



a cavity, relatively spacious, in which I have never seen any 

 spermatozoa ; they cannot therefore be regarded as vesiculae 

 seminales, but probably have a purely secretive function. 



The common vas deferens runs towards the median prostates 

 and then loops round them in a peculiar manner, running in the 

 valley between the two contiguous median prostates. Just after 

 the two still separate ducts, which form by their apposition the 

 common vas deferens, have passed the prostates, there is a slight 

 dilatation of the ducts into which the prostatic tubules open, but 

 quite separately ; that is to say, the left median and left lateral 

 prostate open into the left half, the right median and right 

 lateral prostate into the right half, of the common vas deferens. 



The common vas deferens, after receiving the openings of the 

 prostates, runs on towards the penis as a duct which may be 

 termed, as in other animals, the ductus ejaculatorius (d.ej.). 

 Like the common vas deferens, however, the ductus ejaculatorius 

 is a double-barrelled structure, consisting of two ducts in close 

 contiguity, but with distinct internal cavities. 



At the point where the ductus ejaculatorius enters the penis 

 there is a most singular complication of structure. The proximal 

 end of the penis is prolonged into a spirally coiled organ which, 

 for lack of a better name,* I propose to call the " corkscrew- 

 organ," since it resembles in form a corkscrew, or a spiral drill or 

 borer, of about four turns (c.s.o.). The ductus ejaculatorius runs 

 straight to the base of the corkscrew and through its axis ; at 

 the point where it enters the axis of the corkscrew the ductus 

 ejaculatorius can be seen very plainly to be still double ; it is 

 difficult to make out clearly what happens in the axis of the 

 corkscrew, but when this structure is viewed from the top, it is 

 seen equally plainly that the duct emerges from the axis as a 

 single duct, no longer double-barrelled. It is evident, therefore, 

 that the two ducts that come from the testes, maintaining their 

 individuality and distinctness up to this point, become confluent 

 at some spot in the axis of the screw. This single duct, the duct 



* I regret to say that my meagre acquaintance, which I have not had the 

 leisure to extend, with the vast and scattered literature relating to the 

 anatomical structure of insects, is inadequate to permit me to state whether 

 this or similar organs in other insects have been studied in detail and 

 whether there exists already a special technical term for the structure 

 which I term here in a purely descriptive manner " corkscrew-organ." 



