1903.] MARINE FAUNA OF ZANZIBAR. 173 
specimens are quite complete. The notopodia are the usual 
clavate papille containing a single seta. The neuropodia are as 
in the gill-bearing region, but much smaller. 
The two species P. eliott and P. gardineri are closely related, 
differing only in the reduction of the peristomial collar in the 
latter and the proportions of the mid-body parapodia and setee. 
The only work on the internal anatomy of a member of this 
genus is the section of the fore-body of P. claparedi given by 
McIntosh, although examination of the anatomy of the species 
of Phyllochetopierus would be extremely interesting, both for 
comparison among themselves and with the other genera of the 
family’, especially Chetopterus. Having neither time nor full 
opportunity for this work, to which my inclinations are most 
strongly drawn, I can only give here a few deductions from the 
examination of a series of sections of a specimen of this genus, 
which appear to differ in many minor details from the above- 
mentioned section of P. claparedn. 
Body-wall.—The region A is, as shown by the sections figured 
(BD Xa ies. & 12), an almost solid mass of glandular 
and muscular issues in marked contrast to the delicacy of the 
regions Band C. The whole of the ventral epithelium is strongly 
glandular beyond the limits of the well-marked ventral shield, and 
these glands extend anteriorly to the dorsal surface and even on to 
the prostomium. The cuticle is of extreme delicacy, if really 
present. The musculature consists of weak circular and very 
strong longitudinal muscles, but the division of the latter into 
two dorsal and two ventral bundles cannot be made out. In the 
regions B and C the only muscle occurring dorsally is a very 
delicate circular layer (Pl. XVII. fig. 13). Diagonal fibres can be 
traced in the region A between the nerve-cords and the notopodia, 
which become more definite muscles in the region B (fig. 13), 
The nervous system is in contact with the skin. The two 
ventral cords le at a distance from one another in the region A, 
but approach one another posteriorly (cf. figs. 12 & 13), their 
arrangement corresponding thus to that in Chwtopterus. Trans- 
verse commissures, portions of one of which are shown in Pl. XVII. 
fig. 12, connect the two cords. 
The brain (Pl. XVII. fig. 10), which in Cheetopterus is a narrow 
band dorsal to the mouth, not differentiated from the circum- 
cesophageal commissures, is here more distinct, in correspondence 
with the presence of the prostomium in this genus and its absence 
in the case of Chetopterus. Itis a perfectly simple swelling of the 
circum-cesophageal commissures. The continuity of the nervous 
system with the epidermis is shown by a comparison of the 
sections of the prostomium given in figs. 10 & 11. The former 
shows the circumeesophageal connectives, that on the left as it 
crosses from the ventral to the dorsal side, that on the right, near 
the eye-spot (e) passing into the prostomium. The replacement 
of the ordinary glandular epithelium of this area by the densely 
1 For anatomy of Telepsavus, see pl. xiii. and its explanation in Claparéde’s 
‘ Annélides Sédentaires,’ 
