632 
DK. EUDOLPH VON WILLEMOES-SUHM ON A 
flattened and slightly denticulated at the base. The cornea of the eye is faceted 
externally, the facets being hexagonal (Plate L. fig. 7). Beneath the facets we find very 
elegant slender crystalline bodies, 0840 millim. long, and at the top 0T47 millim. 
broad (Plate L. figs. 9, 9 a). I have figured two pairs of these, as they are always united 
together by their slender ends, the point of union being shown at fig. 9 a. In their 
upper part a granulation is to be seen, giving them a slightly brownish colour ; and in 
their tapering extremities there are some clear vesicles, which have some resemblance to 
the varicosities of a nerve-fibre. The nerve-rods which are present in Plironima are absent 
in this form, and there is no pigment. 
It is impossible to say whether organs of hearing or of touch exist, as it was not 
practicable to dissect the single specimen we procured in order to examine the different 
parts under the microscope. 
The Organs of Digestion and the parts of the Mouth. — The opening of the 
mouth (Plate L. fig. 6, o) is oval, and is situated on the top of an elevation (Plate L. 
fig. 6, A) at the base of the head. It is usually closed by a pair of very small denticulated 
maxillae (fig. 6, ma), and between them a labium (fig. 6, lab) in the form of a small denti- 
culated plate. Other maxillae are entirely wanting; they are physiologically represented 
by two pairs of maxillipeds, which must be regarded morphologically as two pairs of 
ambulatory legs transformed for that purpose. Their relations become apparent on 
comparison with Plironima. These maxillipeds (Plate XLIX. fig. 1, mx) consist of two 
joints, and are terminated by a pair of claws. The external margin of the second joint 
is denticulated. The first pair of maxillipeds is attached to the first segment of the 
thorax, and the second larger pair to the second segment, to which is also attached the 
first pair of ambulatory legs. I therefore think that this larger second segment has 
arisen from the fusion of two segments. 
The small mouth leads into a large slightly yellowish stomach, through a recurved 
oesophageal passage, in which there seems to be a chitinous layer, as a dark spot is to 
be seen there from the outside. The walls of the stomach (Plate XLIX. fig. 3, cce) are 
striated and probably muscular. The stomach appears to be decal, and the particles of 
food brought into it must return in order to get into the intestinal tube, which opens 
from the oesophagus and runs as a thick-walled tube over the right side of the ovary 
(fig. 3, in). Its walls then become thinner and nearly transparent, so that only its 
reddish contents showed me the remainder of the tube running straight to the anus 
(figs. 1 & 2, as), to which muscular fibres, forming a sort of constrictor ani, are 
attached on both sides. 
This configuration of the digestive system is in many respects similar to that in 
Plironima ; the external parts of the mouth, however, bear but little resemblance to 
those in that genus. In Plironima there are one pair of mandibles, two pairs of 
maxillae, and a labium ; while of these we have here only the labium and one pair of 
maxillae. In Plironima the two first pairs of ambulatory legs have no relations to the 
mouth as they have in this case. 
