126 Prof. M'Intosli's Notes from the 



above slightly down^vard and forward. In large specimens 

 the most conspicuous rim is the ventral, which forms a 

 collar as far upward as the median notch on each side, 

 above which is a smooth edge, and then the ventral edge is 

 marked by about six crenations. Each of these is com- 

 paratively broad, with a dimple or depression in the middle 

 of the free edge. They are best seen in large examples. 

 It continues upward as a slightly oblique collar, which has a 

 tendency to be flattened out at the dorsal edge, where it is 

 also somewhat narrowed, tiiough in a large example this is 

 not evident. The general shape is ovoid with a tendency to 

 a somewhat narrower dorsal end. A slight median rid^e 

 occurs from the dorsal to the ventral edge, stopping short of 

 the collar in each case. 



The peristoraial segment has no feature of note except the 

 presence of a lateral furrow on each side, from the notch on 

 the cephalic plate. Tiiis groove passes backward to the 

 sixth bristle-series running above the glandular elevations 

 and hook-rows; and in some it maybe traced a little further 

 backward. The first bristle-bearing segment, like those 

 adjoining, is shorter than those in the centre of the body and 

 more deeply pigmented. Moreover, as Arwidsson has shown, 

 it is largely supplied with glands, and also has non-glandular 

 streaks. The bristles occur as a tuft on each side, and have 

 fairly stout shafts with a short wing distally on the tapering 

 tip (PI. III. fig. 1), which is comparatively short and 

 peculiarly curved. This and the next five segments are 

 shorter than those in the middle of the body. 



The following segment has a bristle-tuft and an elevated 

 pad or ridge with a short row of hooks, the elevation meeting 

 its fellow of the opposite side in the mid-ventral line. In 

 large examples, however, this ridge is less evident, the 

 whole ventral area being glandular, and the same occurs 

 with the third and fourth segments, the rows in these having 

 a gradually increasing number of hooks. The fifth and the 

 sixth segments likewise "liave a thick glandular coating 

 ventrally and ventro-laterally, the long row of hooks and 

 the bristle-tuft in each l)eing at the dorso-lateral edge. A 

 differentiated glandular area lies between the sixth and 

 seventh setigerous regions, the ventral surface being glandu- 

 lar as before. At the eighth the glandular area stretches 

 from the setigerous region of one side to the other, and thus 

 characterizes it, for the eighth segment has only a small 

 triangular patch in front, the ventral surface being devoid 

 of glands until the ninth setigerous area, which is glandular 

 ventrally and laterally up to the bristle-tuft. In the lateral 



