546 ANTHON. [Vor. XIX. 
structure of the salivary gland and the proventricular ceca. 
For the differentiation of the muscle plexus of the czecum, 
Congo-red was the most satisfactory stain. In preparing 
whole mounts of the caecum the best fixation was obtained by 
slitting the animal open for a short distance along the side 
and at once immersing it in a weak Flemming’s solution. 
The best mounts of the mouth parts were made by removing 
the organs and cleaning them in strong carbol-xylol with a 
little safranin in the clearing solution. 
V. THE DIGESTIVE SYSTEM. 
The digestive system of Ctenophora is very like that of 
Holorusia, the allied giant Tipulid, as described by Kellogg. 
(Psyche, June, tg01.) The exceedingly large diverticulum 
is characteristic of the vegetable feeding larve of Tipula and 
Ctenophora. The alimentary canal extends as a straight tube 
from the anterior to the posterior extremity of the body, and 
is nearly wholly enclosed in the coiled perforated sheets of 
adipose tissue. (Fig. 11.) The tube consists first of the long 
slender cesophagus, which opens into the hypopharynx. At 
about the middle of this, the cesophagus is embraced by the 
circumcesophageal commissures and the brain lobes. At its 
posterior end, the cesophagus suddenly dilates and passes into 
the proventriculus, whose diameter is about ten times as great 
as that of the cesophagus. 
The finer structure of the cesophagus, as seen in a cross- 
section, differs in the anterior and posterior part of the tube. 
(Figs. 12 and 13.) The outer cesophageal layer is composed 
of a band of circular muscles, beautifully striated and showing 
large oval nuclei. These nuclei extend over several striations. 
Within this is a doubtful layer composed of a few strands of 
longitudinal muscles, which lie in the cavities formed by the 
invagination of the cesophageal epithelium. At places this 
epithelium is contiguous with the circular muscles and show 
no trace of any longitudinal muscles. Within this muscle 
layer is the much convoluted epithelial layer. This is com- 
