98 M. O. Strobelt wi the Anatomy and 



velope which exhibits numerous longitudinal and transverse 

 grooves, and an inner layer with many dark granular gland- 

 cells. The latter secrete the cement-mass by means of which 

 the egg is attached to the hair of the host. 



The fully developed egg has an oval form (fig. 10), and 

 shows two opposite surfaces, which differ considerably in their 

 curvature. Leuckart calls the convex, more strongly curved 

 surface the ventral, and the opposite but slightly curved one 

 the dorsal surface. He says, u The convex surface corre- 

 sponds to the ventral surface of the young larva. During 

 the sojourn in the ovary the convex surface seems to be gene- 

 rally turned outward towards the lateral parts of the maternal 

 body." As regards the latter part of this statement Leuckart 

 is perfectly right. But it is not the convex but the opposite 

 slightly curved surface that corresponds to the ventral surface 

 of the embryo. The latter lies in the egg so that its head is 

 placed at the upper or anterior pole of the egg y which bears an 

 operculum, and its back on the convex side of the egg, called 

 the ventral surface by Leuckart (fig. 10) ; so that here the 

 denominations dorsal and ventral surface must be reversed. A 

 longitudinal section perpendicular to the above-mentioned two 

 surfaces is the only one that divides the egg into two sym- 

 metrical halves. The egg is always attached to the hair so 

 that the ventral surface of the embryo is turned towards the 

 hair, by which it is enabled, on quitting the egg-capsule, to 

 climb up on the hair immediately. 



The cement-mass, which is on the average 0*336 millim. 

 long and 0*318 millim. broad, consists of a hyaline substance. 

 This presents numerous darker streaks, which, attaching them- 

 selves at the inferior pole of the egg, pass round the hair and 

 unite with the streaks coming from the other side (fig. 10, k). 

 These streaks resemble so many elastic bands, which, on the 

 one hand, maintain the egg in its position, and, on the other, 

 if it should be displaced by external agencies, draw it back 

 again into its place. The hair with the nit attached to it may 

 be best compared, as regards external form, to a tobacco- 

 pipe. The hair represents the tube, the egg the bowl of the 

 pipe, the cement-mass the receptacle, the operculum the lid of 

 the bowl, and the micropylar apparatus the openings in the 

 lid. The operculum of the egg separates in this way : the 

 part lying furthest from the hair first separates from the rest 

 of the chorion, just as, in order to complete the comparison,' 

 the lid of the pipe is attached to the bowl at the point nearest 

 to the tube. 



It is a remarkable phenomenon in the literature of the 

 Fediculina that we find the eggs neither described nor figured 











