100 BRITISH TYROGLYPHID^. 



The nucleus is comparatively large and cyst-like ; 

 rarely there are two nuclei to one cell. The plasma 

 soon changes and a fine-grained yolk-material is formed 

 which stains rapidly and deeply. A nucleolus appears, 

 and a few dark-staining particles in the cell- wall. The 

 eggs push outward in all directions, each surrounds 

 itself with a soft egg-membrane, and at this stage it 

 enters the oviduct. 



With regard to Carpog typhus anonymus Nalepa gives 

 a somewhat different account of the structure of the 

 ovaries ; he says that they are at first globular, after- 

 wards oval; and that they are placed as in T. lonyior, 

 but not so near together. Nalepa further says that the 

 plasma-mass of the ovaries contains not distinct nuclei, 

 but a highly-refractive, finely-granular, nuclear sub- 

 stance arranged in clusters or radial strings ; the for- 

 mation of the cell he describes as taking place near the 

 mouth of the tube from the receptaculum seminis ; the 

 eggs are thus impregnated immediately they are formed. 

 They draw toward the exterior and assume a semilunar 

 form. The other contents of the ovary are finely 

 granular, and do not colour. The egg, Nalepa states, 

 now becomes oval ; the plasma-mass divides and lies at 

 the two poles in half-moon-shaped nuclear masses, 

 separated by a clear, finely- granular zone ; the con- 

 tents increase, and in the scarcely coloured part four or 

 more deeply- stained nuclei, round or hemispherical, 

 may be detected. In this stage Nalepa saw in the cell- 

 wall numerous small, dark-staining bodies whose origin 

 and purpose he could not trace. 



The Oviducts. PL B, fig. 8; PI. C, fig. 1, od. 



These in all species which have been properly investi- 

 gated are very similar in character ; they consist of 

 a long tube starting from the anterior end of each 

 ovary, which is opposite to that where the passage 

 from the receptaculum seminis enters ; these tubes 

 join together to form the vagina, and thus with the 



