222 D. J. SCOURFIELD ON EPHIPPIA OF LYNCEID ENTOMOSTRACA. 



ventral angle, thus leaving a small piece of the old shell margin 

 intact. This feature is exactly similar to what is found in 

 the ephippium of Bosniina (see 11), and it will be seen, as 

 we proceed, to be of very common occurrence among the 

 Lynceid ephippia. Careful examination of the ventral edge 

 of the ephippium will show that, from the anterior edge to 

 within a short distance of its posterior termination, there is 

 a narrow border of finely pitted chitin. The origin of this 

 will be seen presently. The surface of the ephippium shows 

 the characteristic longitudinal stripes and also the fine 

 intermediate " scratchings " present in the ordinary shell ; 

 and these markings do not seem to be in any way modified 

 in this species, except that where the ephippium is darkest, 

 i.e. just over the egg, the long parallel lines show a slight 

 tendency to be rather better defined than usual. As regards 

 the J darkening of the shell, which may be very intense, even 

 making the ephippium appear almost black to the naked 

 eye, it must be pointed out that it is really limited to a 

 comparatively small oval area, the situation of which will 

 be seen indicated in Fig. 4. The chitin of this dark brown 

 area does not, however, appear to be altered in structure, as 

 is so often the case in other ephippia. 



So far only the outside of the ephippium has been dealt 

 with. We can now turn our attention to the interior ; and 

 here it will be found that the solitary egg is not simply 

 lodged in the case just described, but is surrounded by a 

 sheath of exceedingly delicate crumpled membranes. These 

 do not touch the egg, at least not as seen from the side, 

 but stand ofi:' at some distance, as figured. They undoubtedly 

 represent the moulted inner lining of the valves, just as the 

 external part of the ephippium is evidently the exuviated 

 outer coat. It is not intended in this paper to specially 

 consider the winter eggs contained in the ephippia, but it 

 may be noticed in passing that the single egg* in this species 

 is rather longer in proportion to its width than that of any 



* Weismann (12) says that there may be two winter eggs in 

 CamptocerciLS macrurus, and he gives a figure of an ephippial female 

 with two such eggs (Taf. vii., Fig. 9). Whether this really represents a 

 difference between the species of the genus or not is uncertain. Professor 

 tsars informs me that he has never seen more than one winter egg in 

 any Lynceid except Eurycerciis ; and this has been my experience. 



