Gatty Marine Laboratory^ St. Andrews. 259 



tubes after preservation, the caudal region is thrown into 

 various zig-zags or spirals^ and the tufts of bristles are 

 more conspicuous than in front. One or two of the terminal 

 bristles are single on each side, those preceding being in 

 groups of two, three, four, and five or more. In certain 

 examples, in lateral view, the ventral process at the tip 

 of the tail projects more than the dorsal, though, perhaps, 

 irregularity of the dorsal lobes occasionally occurs. The 

 arrangement of the septa is apparently on a similar plan 

 to that in Oivenia, where they are very distinct. The 

 septa in Myriochele probably cause the constrictions, and 

 the tips of the lozenge-shaped sections of the intestine are 

 fixed by membranous attachments to the body-wall. A 

 pinnate aspect is apparently due to the blood collecting at 

 the septa, where it was darkened by the stain (haematoxylin). 

 The reproductive elements appear to be lodged on each side 

 posteriorly, but their mode of exit has not been demon- 

 strated. So far as could be made out, no pores were present 

 posteriorly. 



In sagittal sections of the tail (PI. X. fig. 33) the 

 constriction present a short distance from the tip appears 

 to be normal, the gut being narrowed at this point and 

 furnished with a valvular process projecting forward [val.p.). 

 The terminal region of the body thus marked off is divided 

 dorsally into five compartments by short transverse septa, 

 on the anterior faces of which layers of blood occur, probably 

 from extravasation, as no walls other than the septa are 

 visible. The continuation of comparatively large intestinal 

 sinuses almost to the tip of the tail, in addition to the ventral 

 trunk, indicates their importance in the economy of the 

 annelid, probably in connection with a respiratory function. 



The transverse sections of the extreme tip of the tail show 

 a ring of hypoderm with a ventral gap (PI. X. fig. 34), on 

 each side of which the wall is thickened, so that it is lobate. 

 Moreover, a differentiation occurs in this lobate part, as if an 

 aperture existed; but such may be due simply to the more 

 vacuolated condition of the hypoderm of this region. The 

 cells are larger than on the dorsal surface, and after the 

 completion of the posterior aperture they form a distinct 

 pale area on each side of the middle line (PI. X. fig. 35). 

 The gut shows, almost before its closure, traces of the vascular 

 sinus (PI. X. fig. 35, vs.) on each side, the blood in which had 

 been rendered of a deep purplish-black hue by the action of 

 haematoxylin ; and soon the ventral vessel appears, tlie lateral 

 sinuses greatly increase in size, whilst ova are present between 

 the ventral vessel and the b<idy-\vall, the nuclei in these being 



