DEVELOPMENT OF PERIPATUS CAPENSIS. 
781 
Fig. 5. Spermatozoa without a nucleus, from the ovary of a female specimen, and as 
they occur in the lower part of the vas deferens of the male, mingled, how- 
ever, there with others retaining the nucleus and free nuclei. 
The actual length of the ripe spermatozoa appears to be about three times 
that of an ovarian ovum, or about *5 millim. 
PLATE LXXV. 
Various stages in the development of Peripatus, from embryos taken from the uterus 
of various female specimens. 
Fig. 1. Earliest stage of the embryo observed, as seen within its envelope; the cephalic 
lobes are formed ; the anterior part of the body shows a definite segmenta- 
tion. On the three segments immediately succeeding the cephalic, the outer 
layer is rising up to form the members. 
Fig. 2. Embryo, somewhat more advanced, removed from the envelope and viewed 
from the ventral surface by transmitted light in optical section. 
a. Antennae, c. Cephalic lobes. 1. First pair of body-members, form- 
ing later the maxillae. 2. Second pair, perforated later by the 
ejaculatory duct of the slime-gland. 3. Third pair, afterwards first 
pair of ambulacral appendages. 
o. Mouth, i. Intestine. (The same numbers and letters in the succeed- 
ing figures have the same signification.) 
The second pair of members are the longest, and continue so for a consi- 
derable period ; ultimately in the adult each is represented only by a small 
papilla. 
The cephalic lobes are hollow ; a fold rising up in the roof of their cavity 
divides them into two. Their structure is identical with that of the posterior 
members (see Plate LXXIII. fig. 9). The limbs first appear as undulations 
of the body-wall ; they form from before backwards, and anteriorly to the 
segments of the body. Before the appearance of the members segmentation of 
the body is marked by a transverse line. The segmentation disappears after 
the members are formed. The intestine is connected by lateral projections 
with the folded interspaces between the limbs (see Plate LXXIII. fig. 9). 
Fig. 3. Embryo in a further state of advancement removed from the envelope, and as 
seen by reflected light : a, from behind ; h , from in front. The number of 
body-members is complete, viz. nineteen, of which the first becomes the oral 
and the nineteenth the anal papilla. A saddle-shaped mass of yelk remains , 
on the dorsal surface opposite the seventh, eighth, and ninth pairs of mem- 
bers. The mouth and anus are sketched out ; the cephalic lobes (c) show a 
lateral depression dividing them into two regions, anterior and posterior. 
The anterior members are most perfectly formed ; the antennae (a) already 
show jointing. Actual length 5’5 millims. 
