DEVELOPMENT OE PEEIPATUS CAPENSIS. 
779 
The tracheae here are represented, for convenience of drawing, as dark on 
a light ground ; in reality, when observed by reflected light, they have the 
usual pearly lustre so characteristic of tracheae when full of air. Exteriorly 
to the ventral nerve-cords ( v.c . v.c .) are seen the rows of openings com- 
municating with the feet, and probably vascular, described by Grube. 
Fig. 3. Hinder part of the body of male Peripatus, laid open from the back. The 
stomach and short intestine have been turned down, in order to show the 
arrangement of parts behind them. 
v.s. Yesiculae seminales ; t. Testes; pr. Prostate; v.d. Yasa deferentia ; 
p. Enlargement of azygos terminal portion of male duct, ejaculatory 
duct, or penis'? a.g. Accessory gland; v.c. Ventral nerve-cords; 
s. Stomach ; i. Intestine. 
PLATE LXXIII. 
Fig. 1 . Tracheal twig from . the wall of the uterus, to show the manner of branching. 
Branching, however, is very exceptional. 
Fig. 2. a. Arrangement of the tracheae on wall of one of the fine tubes of the slime- 
gland. There is here no branching. 
b. Small portion of one of these tracheae as seen with Hartnack’s No. 8, 
ocular 3. Transverse lines indicate the existence of an internal spiral band, 
which is broad in proportion to the diameter of the tube. Actual diameter 
of the tube ’003 millim. 
Fig. 3. Cells from the mucous surface of the stomach. 
a. Liver-cell ; b. Slime-cell ; c. Aggregation of oil-globules. Actual dia- 
meter of liver-cell ‘04 millim. ; others in proportion. 
Fig. 4. Portion of one of the viscid threads which are shot out by Peripatus and form 
meshworks. 
Fig. 5. Vertical and transverse section through the ventral wall of the body, to show 
the origin of the tracheae. 
a. Epidermis, by reason of the thickness of the section, showing to the 
left two of the warty protuberances with which the surface of the 
animal’s body is covered. 
b. Region occupied by oblique or decussating muscular fibres. 
c. Layer of transverse muscles. 
From a pit at the base of one of the cutaneous warts arises a simple short 
tube, from the inner end of which pass otf an enormous number of fine 
tracheae. These latter do not branch, but arise all directly from the end of 
the tube, and at their origin are so closely packed as, with their contained 
air, to prevent the transmission of any light. Some of the tracheae of the 
bundle are distributed at once to the skin and muscles. 
