PA RASITIC COPEPODS— CA LIGIDJE— WILSON. 



527 



length (e., fig. 32). In addition to forming a cylindrical tube in which 

 the eggs arc arranged like a roll of lozenges, the cement gland also 

 pours out a layer of its secretion between every two adjacent eggs. 

 This forms a membranous partition and divides the egg tube into a 

 scries of narrow compartments, in each of which is a single egg, which 

 does not quite till the space, leaving room for the subsequent develop- 

 ment of the larva. 



The spermaries or sperm receptacles (s. r.) consist of a sack on 

 either side extending from the os uteri obliquely inward and forward 

 to the median line where it joins its fellow from the opposite side 

 (fig. 33). A canal, the vagina (va.), leads diagonally backward and 

 inward from the center of the posterior margin of each sack and opens 

 to the exterior on the posterior margin of the genital segment along- 



Fig. 33. — Semen receptacles and vagina of a female Lepeophtheirus. (Partly after Claus.) 

 e. g., cement glands; <1, cement gland duct; e. c, egg cases; s, spermatophores; s. r., sperma- 



Kll'.s; V, VULVA; Va., VAGINA; 5, FIFTH LEGS. 



side the mid line. This is the vulva or sexual opening (v.) and just 

 inside it the vagina is enlarged considerably for the reception of the 

 spermatophores (s.). These spermatophores are white in color for 

 nearly all the species. They do not alwa} r s enter the vulva, but may 

 often be found upon the external surface, usually in the immediate 

 vicinity of the vulva but sometimes elsewhere. On species like Lepe- 

 ophtJu irus edwardsi and Caligiis rapax which are well pigmented they 

 show up very prominently against the dark background. 



A single copulation takes place just after the close of the chalimus 

 stage, and at that time these semen receptacles are rilled Iry the male. 

 Their ((intents probably suffice for the fertilization of all the eggs the 

 female lays, during her entire life. 



The sexual organs of the male are very similar in position and ar- 

 rangement to those of the female (Hg. 34). They consist of a pair of 



