CRUbTACEA. 325 



orifice of the male organ, and he seizes the tube as soon as it has 

 escaped, and glues it to the abdomen of the female above the vulva. 

 No female has this tube prior to the coitus, and none is without it 

 afterwards. A male fit for coitus always has this tube or spermato- 

 phore in the lower dilated half of his seminal canal, and after the 

 coitus it is no longer there. Professor Siebold* has found the sperm- 

 tube attached to the rounded end of the last pair of feet of the 

 male, indicating the instrument of fixation. The females so pro- 

 vided are not, therefore, disdained by other males, — three, four, or 

 even six sperm-tubes may be found attached to the same female. 

 The sperm-tube consists of three different kinds of substance, sper- 

 matic matter, expulsatory cells, and agglutinating fluid. The 

 action of the cells, in expanding, is to push out the spermatozoa, 

 which, as the sac is suspended to the ventral surface of the first 

 caudal segment, thus escape close to the vulva. 



The Cyclops has a single testis, which is a pyriform sac concealed 

 in the dorsal region, beneath or behind the heart. A long and wide 

 sperm-duct descends to the inferior half of the body ; then rises 

 abruptly, and again descends by a sudden curve, to arrive at the 

 sexual opening, which is simple, and at the middle of the base of the 

 tail. In the pyriform testis are sperm-cells and also spermatozoa. In 

 the descending part of the sperm-duct is the spermatophore, which is 

 homotypal with the ovicapsule. 



How they become occupied with their proper threefold contents 

 has not been observed, but it does take place gradually as the sper- 

 matophore descends towards the spermatic outlet. There is no 

 proper coitus, i.e., the male does not intromit directly ; but he appends 

 or attaches the spermatophore to the female. Each spermatophore 

 contains, besides spermatozoa, two other substances ; one expulsatory, 

 which swells in water, and expels the spermatozoa ; the other coagu- 

 lates in the water, and serves for the attachment of the spermatophore. 

 The contemplation of the complex machinery requisite for this 

 curious mode of impregnation, whilst it exemplifies the necessity of 

 direct contact of tlie spermatozoa with the ova, must fill the mind 

 with admiration at the unusual interdependent arrangement, or, 

 humanly speaking, contrivance, which is manifested in subserviency 

 to the propagation of an animal so minute and seemingly so insig- 

 nificant. 



In the genus Cypris the ovaria consists of two long cagcums, 

 curved, and applied to the sides of the hinder half of body, but 



* LV. p. 36. ; also the excellent supplementary remarks by Mr. Lubbock, 



cccxxv. 



Y 3 



