1895.] HYJ)EACHlfID rOOfD I> COBK-VVALl,. 193 



lobes by the swelling and rounding of its dorsal and lateral 

 surfaces both, anteriorly and posteriorly, leaving a thinner and 

 narrower portion between, but without any breach of continuity 

 or line of demarcation ; the whole forms one piece. The mass 

 varies a good deal in form in different specimens, and even the 

 two sides of the same individual are seldom quite similar, but the 

 general shape always corresponds fairly well. The masses on the 

 two sides of the body are a short distance apart anteriorly, but 

 approach each other closely posteriorly : almost at their hinder 

 ends they are joined by a short bridge (fig. 17) quite continuous 

 with both sides, so that the organ on both sides of the body forms 

 one unbroken whole. From the ventral surface of the narrower 

 part of the testicular mass on each side proceeds a vas deferens of 

 moderate length, which runs upward and forward. At its anterior 

 (distal) end, which is nearest to the dorsum, this vas deferens joins 

 its fellow from the opposite side of the body, and the two enter a 

 short widish ductus ejaculatorius (figs. 17, 18, 23, de.) with very 

 fleshy walls, which runs downward and a little forward. This 

 organ is inversely pyriform, being narrowed at its distal end so as 

 to discharge by quite a small opening into a very large penial canal 

 (figs. 18, 23, j^Jc), which again is inversely pyriform, its largest 

 part being near to where the ductus ejaculatorius enters ; this 

 canal proceeds almost perpendicularly downward. On the outside 

 of the widest part of the canal is a chitiuous bar (fig. 18, c6.), from 

 which a series of diagonal muscles (fig. 18, mc.) spread out; so 

 that those on the two sides of the body, acting siraultaneousl}', 

 would form powerful compressors. Longitudinal mu'^cles also run 

 from the ductus ejaculatorius to the inner side of the cuticle of the 

 body close to the genital opening ; thus the penial canal can be 

 compressed longitudinally as well as transversely. The canal 

 itself is a large, membranous, tubular organ, considerably and 

 irregularly folded, so that the portion nearest to the ductus 

 ejaculatorius is apt to form a series of pouches, and the more 

 distal part a number of longitudinal folds converging to the genital 

 aperture. This last-named part is not much hidden by muscles 

 when the organ is dissected out, whereas the more bulbous proximal 

 portion is almost surrounded by them. I have not been able to 

 discover any chitinous penis such as Croneberg draws in Trorn- 

 hiclium. The penial canal, as I have drawn and described it, is as 

 at rest under ordinary conditions. I have not been able to 

 examine it at the moment of coition, and therefore 1 am not able 

 to say whether the membranous tube is evaginated — thus, in effect, 

 forming a penis, which seems very probable, — or whether the sperm 

 is simply deposited on the exterior of the female, or conveyed by 

 the feet as observed by Koenike in Curvipes fuscatus. 



The testicular mass appears to be one solid block (subject to the 

 foregoing description of its shape), and there is not any line of 

 demarcation or any membrane or division between its various parts ; 

 but still it is not really so. The greater part of it has an external 

 coating of a single layer of large cells about "015 mm. in diameter, 



Pboc. Zool. Soo.— 1895, No. XIII. 13 



