380 Introduction to Animal Morphology. 



but with two oviducts opening separately. Opening 

 into the vulva, rarely into the oviduct, are two stalked 

 receptacula seminis and a pair of cement glands, 

 whereby the eggs are stuck together. The testes are 

 double (lulidse, Glomeris) or single, with, in the former 

 case, one vas deferens between them ; in the latter a 

 series of lateral pouches communicates with a central 

 convoluted vas deferens, which dilates or divides into 

 two, which either open separately on small papillae, or 

 again unite, and form a small penis ; 1-3 pair of ac- 

 cessory glands, for the secretion of adhesive matter to 

 make spermaphores, are appended to the end of the 

 vas, as well as vesiculee seminales. The females are 

 larger than the males. The genital openings are 

 posterior in Scolopendra, or between the second and 

 third body ring in Chilognatha, in which sometimes 

 the male has a double spiculum on the seventh seg- 

 ment, which carries the spermaphores from the opening 

 of the vas to the female vulva. The ova are laid in 

 the ground, and in development form two germ- 

 layers, an outer neuro-epithclial^ and an inner, which 

 divides into many protovertebra-like bodies, giving 

 rise to the muscular and other systems. The primary 

 neural region in the ^^^ is concave, and the embryo 

 is invested with a structureless larval skin, like that of 

 Crustaceans and Acari. The larvae are apodous or 

 hexapod, and the number of legs increases at every 

 moult, and the eyes and antennae afterwards develop ; 

 the terminal rings are the first developed, then the in- 

 termediate. Some Scolopendra are viviparous. The 

 bite of some is poisonous, as the foot-jaws have a 

 poison-gland. They are largest in the tropics. 



