b A. D. MICHAEL ON AN UNDESCRIBED 



points, which, in some of the hairs, are of extreme length, and are 

 curved, or doubly-curved. These hairs, or scales, vary greatly, 

 hardly any two (except the corresponding hairs on the opposite 

 sides of the body) being alike. The arrangement (which is not 

 quite the same as in M. musculi) is as follows : — 



There are five pairs down the centre of the back, of which the first 

 and fifth pairs are less spatulate than the others. On each side of 

 each of the first three of these pairs is a hair or scale, thus forming 

 three transverse rows of four, of which the lateral are not quite in a 

 line with the central pair; the lateral are the largest, the anterior of 

 them (Fig. 10) being far the broadest and the posterior (Fig. 11) 

 the longest on the dorsum. These hairs have longitudinal ridges 

 running along them ; there are seven or eight of these ridges on the 

 broadest hairs, and two or three on the narrowest. In addition to 

 these there is an irregular circle of spike-like or rod-like spines, some 

 more or less curved, set round the vulva, which is placed on a consider- 

 able elevation near the posterior end of the creature. The spatulate 

 hairs cover up the greater part of the dorsal surface, and they do not 

 appear to be attached in the ordinary mode of that class of hair or 

 scale, i.e., by a peduncle springing from the proximal edge, and con- 

 tinued in the plane of the scale, but are almost sessile, the peduncle 

 being very short and thick, and placed underneath, and at right- 

 angles to, the scale, the point of attachment being the centre of the 

 curve formed by the proximal end of the scale; thus the peduncle 

 shows, in optical transverse section, through the semi-transparent 

 scale. 



The claw of the first leg (Fig. 6) varies considerably from the 

 same part in M . musculi, being much broader and more truncated 

 and scoop-like, and the hook-like or curled portion, which curves 

 under the hair of the host which the parasite is clinging to, being 

 smaller and narrower in proportion to the whole claw, if indeed this 

 vice-like apparatus can be called a claw at all. The expanded 

 lamina of the claw is semi-transparent, but has a curious branched 

 thickening running along its upper surface, a spine being inserted in 

 most of the places where a branch strikes the periphery of the claw. 

 There is a short truncated spine behind the claw, and a strange 

 chitinous piece behind that, like somewhat more than half a hollow 

 sphere, both like those in M. musculi, but not quite so large in pro- 

 portion, and not quite identical in form. 



The claw of the second leg (Fig. 7) is didactyle, and is the 



