786 



REPRODUCTIVE ORGANS AND GENITAL ARTERIES. 



off minute branches, which pass deeply into the recesses of the follicular ridges and are 

 doubtless the means by which nutriment is conveyed to the vitellus. I noticed that 



_- t^a. 



gen. a. 



Fig. 11. 'N. poinpilius. Fresh ovarian ovum showing the areolation produced by the folds of the egg-follicle 

 which project into the yolk. p. a. pellucid polar area, in the centre of which the germinal tract lies. 



Fig. 12. Ovary of an injected specimen from above, o.a. neck of the gonad with orifice at its free end ; 

 o. ova seen through the transparent capsule of the ovary, with areolations partly drawn to show difference 

 in size of meshes in older (wide meshes) and younger eggs ; geii.a. dorsal branch of genital artery. 

 [From Quart. J. Micr. Sc. Vol. 39, 1896.] 



the deep-lying branches anastomose with one another, thus forming a rete mirahile, while 

 the superficial branches appear not to form anastomoses. 



The germinal tract appears in the centre of the clear polar area of the fresh egg 

 as a faint whitish spot upon the ventral aspect of the ova as they lie within the ovary 

 (Text-fig. 13). The older ovarian ova are rendered somewhat shapeless by mutual pressure 

 with a roughly oval outline, and measure 15"5 mm. in length with a maximum breadth 

 of 11 "5 mm. When the pressure is relieved by slitting open the ovary the ova round 



.p.a. 



Fio. 13. N. pompilius, ? . Reproductive organs seen from below in fresh condition, p.a. polar areas of 

 ovarian ova; o.a. orifice of the ovary projecting into the ostium abdominale of the oviduct; g. uterine 

 portion of oviduct ; v. vaginal portion of oviduct. [From Quart. J. Micr. Sc. Vol. 39, 1896.] 



up, and those which are submature have an average diameter of about 10 mm. The 

 yolk is viscous and glutinous with a translucent brownish colour. 



