THE DEVELOPMENT OP PERIPATUS CAPENSIS. 
465 
dorsally. The salivary glands are, as I have said in my pre- 
liminary paper, the nephridia of the third somite, i. e. the somite 
of the oral papillae. 
The remaining nephridia are also visible through the skin, 
those of the fourth and fifth legs being especially conspicuous 
by their greater size. 
Fig. 38 represents this embryo in its natural position within 
the uterus, a position which is retained until birth. 
From January onwards the changes are merely those of 
growth. When the young are born, i. e. in May, the antennae 
are green, but the rest of the body is either quite white or of a 
reddish colour. This red colour differs, however, essentially 
from that of the adult, in the fact that it is soluble in spirit. 
The just born young vary considerably in size, the average size 
in the case of Peripatus capensis being from 10 — 15 mm. 
The just born young of Peripatus Balfouri are about half 
this size. 
EXPLANATION OF PLATES XXXI and XXXII, 
Illustrating Mr. Sedgwick’s Paper on “ The Development of 
Peripatus Capensis.” 
List of Reference Letters. 
a. Anterior end. a. Anus. an. p. Anal papillae. At. Antennae, c. g. 
Groove in brain, d. Dorsal ectodermal thickening, e. Eye. ec. Ectoderm. 
en. Endoderm. F. 1 . . . . fyc. Feet. j. Jaw. j. s. Swellings at base of 
jaws. L. Lip. M. Mouth, me. Mesenteron. or. p. Oral papillae, o. s. 
Opening of salivary gland, p. s. Praeoral somite. R. Rectum, s. 20. 20th 
somite, s. g. Salivary glands, si. g. Slime glands, s.o. 4 and 5. Nephridia 
of 4th and 5th legs. st. Ectodermal ingrowths into embryonic mouth. 
PLATE XXXI. 
All the figures on this Plate, except 15, 17 — 22, are from fresh specimens. 
Fig. 1. — Per. Balfouri. Side view of unsegmented ovum, showing polar 
bodies and dark patch. Greatest length ‘4 to '48 mm. 
