A CONTRIBUTION TO THE ANNELIDA. 57 
and another even more closely approximated pair on the ventral 
surface of the snout in front of the two prominent pads of the 
mouth (ibid., ocv.), and thus separated from the dorsal pair by 
a considerable interval. Functionally thus the one pair serve 
as organs of vision dorsally, the other for use ventrally. The 
eyes have a distinct capsule with a broad margin of pale co- 
lumuar cells, within which is the dense black pigment. 
In Spinther the tentacle is apparently homologous with the 
caruncle in the present genus. It lies over the cephalic nerve- 
mass, is supplied with two large nerves, four eyes, and con- 
siderably developed hypoderm, but the latter and the muscular 
strands are much more largely developed in Euphrosyne, 
and the organ is more complex. Vertical muscles pass from 
the nerve-cords inferiorly in Spinther, and other muscles 
from the lateral regions outside the pharynx, but they are less 
developed than in Euphrosyne. The situation of the eyes in 
Spinther, however, diverges, since both pairs are dorsal in 
position, being located at the anterior and posterior margins 
of the tentacle. The figures of Drasche! and von Graff,’ as 
well as my own sections of Spinther miniaceus, Grube,’ 
show that the minute structure of the eyes is the same in both 
genera. 
In Euphrosyne cirrata the dorsal eyes lie on each side 
of the anterior region formed by the fusion of the tentacle 
with the caruncle. They have a somewhat radiate arrange- 
ment of the clear vesicles with a dense ring of pigment, and lie 
in the hypoderm—with the cuticle externally. The ventral pair 
are more widely separated than the dorsal, but have the same 
structure and relations to the hypoderm and cuticle. 
Branchiwe.—Externally are the cuticle and its cilia—with 
the thick hypodermic layer beneath—both layers being con- 
tinuous with those of the body-wall. Moreover, vertical bands 
of muscular fibres pass through the circular and other layers 
to the bases of the branchial stems, enter the latter, and form 
1 «Anat. von 8. miniaceus, Grube,’ Wien, 1885, p. 10, Taf. ii. 
2 Op. cit. 
* I am indebted to Professor L. von Graff for various examples of this 
species, 
