544 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



mentioned compact coil and pass forward as a more or 

 less straight duct. 



At the beginning of this straight portion signs of 

 segmentation begin to appear on the upper side only of 

 the chitinous tube containing the sperms (fig. 41). These 

 constrictions deepen till the sperm band presents very- 

 much the appearance of the colon of higher mammals, 

 and finally it becomes cut into a series of lobes united by 

 a continuous base — each lobe containing a large number 

 of spermatozoa (fig. 42). The lobes, as we go further 

 down the tube, gradually assume the shape of the 

 finished spermatophore (fig. 43), and on reaching the 

 vas deferens, the strip of membrane on which they are 

 placed like a fringe breaks into convenient lengths — four 

 or five spermatophores being placed on each strip. 



The vas deferens, which is crowded with such strips, 

 is a thin-walled broad tube of considerable length. It 

 becomes narrower on reaching the thorax and this 

 narrow part is continued to the communication with the 

 exterior — it is called the ductus ejaculatorius. The 

 whole gonad from the germinal portion to the end of the 

 ejaculatory duct is one uninterrupted tube. 



Spermatozoa (fig. 44, a and b) — The sperms are 

 quite characteristic bodies. They appear, in the living 

 material, to consist of a clear capsule from which spring, 

 near the base, three long processes. Stained preparations 

 show that the detailed structure is based on the same lines 

 as those usual among the marine decapod Crustacea. 

 There is a vase-shaped head, down the centre of which 

 runs a hollow column with dorsal and ventral orifices. 

 The cephalic vesicle is clear and it rests on a collar from 

 which three processes spring. Under the collar is a 

 somewhat irregular vesicle of granular protoplasm, 

 which readily stains. Retzius describes an anterior 



