88 Dr. F. Muller on Entoniscus Porcellanse, 



less ; it is almost entirely filled by the liver and ovaries, which 

 immediately strike the eye by their vivid coloration, the former 

 being of a splendid deep orange-colour, and the latter reddish 

 violet. The liver consists of two tubes, about 0*2 to 0*3 millim. 

 in width, placed close together on the ventral surface, which 

 commence csecally at the posterior extremity of the thorax, and 

 extend to the head. The ovaries occupy the back, upon which 

 they project in irregular eminences, leaving anteriorly as much 

 free space as the liver does behind. Feet I have generally entirely 

 missed finding, even in young females, which, from their less- 

 developed brood-plates, are more easily examined for them. 

 Sometimes, however, and, indeed, not in very young specimens, 

 I found one or two, in the form of short, pointed, conical points, 

 curved backwards and beset with small scattered bristles. The 

 brood-plates, on the other hand, are developed into enormous, 

 much-folded, lobate and slit membranous lobes. When I could 

 count them distinctly (for frequently they appear as a single, 

 large, almost inextricable laminar frill), I found six pairs ! They 

 are permeated by narrow arborescent ducts, into which the 

 biliary secretion from the ruptured liver may sometimes be 

 driven by the pressure of the glass cover, and contain extremely 

 numerous, densely aggregated, fatty globules. 



If we are astonished, even in BopyruSy at the quantity of eggs 

 which accumulates under its broad shield-like thorax, this is 

 still more surprising in Entoniscus : the eggs form irregularly 

 aggregated masses, often equal in width to the length of the 

 thorax, which they sometimes far exceed both before and behind, 

 so that not unfrequently the whole body is completely concealed 

 in them. And whilst Bopyrus, like other Isopods, allows each 

 brood to become perfectly developed and to escape before laying 

 new eggs, Entoniscus accumulates a whole series of consecutive 

 broods about it simultaneously; so that the material for the 

 whole developmental history might be obtained from the brood- 

 leaves of the same animal. 



The thorax is followed by a much thinner and extremely mo- 

 bile six-jointed abdomen, of vpry variable length, sometimes 

 much shorter than, sometimes more than half as long again as, 

 the thorax. These differences in its length arise chiefly from 

 the first two segments, which are produced into long cylinders. 

 In an animal 14 millim. in length, I find the length of the first 

 abdominal segment 2'3; of the second, 2; of the third, 1*2; 

 of the fourth, 0-32; of the fifth, 0*25; and of the sixth, 0*38 

 millim. The thickness of the first segment was 0*25, and that 

 of the last 0*2 millim. The first five segments each bear a pair 

 of inarticulate, sword-shaped feet, without any bristles, near their 

 posterior extremity ; those of the third pair are the longest, and 



