368 
THE VOYAGE OF H.M.S. CHALLENGER. 
whole organ is striated transversely. When more highly magnified (PI. XXIIIa. fig. 14) 
the strise are observed to become oblique in direction just below the pale terminal region. 
As a rule the inferior bristles are the shorter, and there is not much difference in size 
between those of the fifth tuft and the last. When the Annelid is placed on its dorsum, 
both these and the dorsal bristles are included in what appears to be the ventral area, but 
of course the flaccidity of the body causes some exceptional features in this respect. 
The oral aperture is in the form of a considerable anterior slit, having dorsally six 
madder-brown branchiae with pale tips, arranged along the dorsal arch of the aperture. 
Ventrally are the two great foliaceous lamellar tentacles with a deep inferior groove. 
Two parasitic [T7'ophoniphila hradii, n. sp.^) adhered to the bases of the branchiae, 
their smooth yellowish bodies (ovisacs) projecting into the mouth, while the anterior end 
was imbedded in the tissues. In shape each is somewhat fusiform or elongate-ovoid 
(PI. XXXVIa. fig. 4), the anterior end being more pointed than the posterior, 
indeed, in some views the aspect is slightly clavate. One had a brownish globular 
anterior region with two papillae and a process which was attached to the base of the 
branchia. The other had only a broAvnish mucronate surface. The chitinous body formed 
a chamber for the reception of the eggs. Levinsen - describes a species in Brada villosa, 
H. Pathke, but this has a much larger anterior region, which is also reflexed. There are 
also two ovisacs, Avhich are attached a short distance in front of the posterior end. It 
thus differs considerably from Trophonip)hila, which indeed is nearer the larval form of 
Levinsen’s species. 
The oesophagus (PI. XXXVIa. fig. 5, a) is somewhat dusky anteriorly, passes back- 
Avard AAdth a cuiwe to the left, and is continuous Avith the stomachal region, though there 
is no definite boundary-line. The intestine is remarkably elongated, probably nearly 
four times the length of the animal, an unusual feature in the Annelids. The greate]' 
part of this is formed by the anterior or smaller gut (PI. XXXVIa. fig. 5, 5, B), the large 
intestine (d) being rather shorter. The junction betAveen the two parts is marked 
by a somewhat constricted region in the anterior gut, which is thus boldly defined from 
the larger intestine. A slight diminution (e) again occurs a little in front of the anus {/). 
The foregoing alimentary canal is coiled in a complex manner in the perivisceral 
chamber, and from the margin of the canal a mesentery (c, c') composed of a beautiful 
network of blood-vessels passes off. These blood-vessels are of considerable size, and 
must perform important functions. They seem to be more slender at their junction with 
the canal immediately behind the attachment of the fimbriated termination of the 
proboscis. A little further backward, again, they form remarkabl}^ flattened expansions, 
so that the apertures in the mesliAvork are less than the tubular parts. Under a lens the 
edges of these fine vascular tAvigs are studded with minute proces ses like microscopic beads, 
1 After Prof. G. S. Brady, of Durham University, author of many valuable memoirs on the Ostracoda and Copepoda. 
2 Vidensk. Meddel.f. d. nat. Foren. i Kjipbenhavn, 1877, p. 371, woodcuts C-E. 
