10 MM. Kowalevsky and Barrois on Anchinia. 
peduncle (fig. 1, nos. 4 and 5). In it the internal organs present 
relations absolutely different from those which we have seen 
in the preceding stage. The cloacal sac is now formed; it 
occupies the space situated between the ganglionic mass and 
the peduncle, and presses upwards the ganglionic mass. In 
consequence the latter, which was previously placed towards 
the middle of the dorsal surface of the bud, is approximated 
to its upper part (figs. 1, 3, 4), while the endostyle quits that 
position to be more or less completely pushed over towards 
the ventral surface. 
The pharyngeal sac of the preceding stage, as well as the 
cloaca, 1s in communication with the exterior world; the two 
apertures (incurrent and excurrent) exist, and are each of them 
surrounded by two muscles; the digestive tube is completed 
by the addition of an intestine which opens into the cloaca; 
and, as before, there exists a rounded stomach, which consti- 
tutes its most voluminous part. 
The endostyle has already more restricted dimensions 
relatively to those of the surrounding organs; in its middle 
part it presents a deep groove which divides it into two parts. 
The pharyngeal sac begins to present a thickening (/ v), 
which forms the first indication of the vibratile band. 
The ganglionic masses possess a much more definite struc- 
ture than in the preceding stage. There may be distin- 
guished in it two very distinct parts :—(1) a hollow portion 
united to the pharyngeal sac by a hollow peduncle, and which 
appears to be only a cecal expansion of the wall of that sac; 
and (2) a solid portion surmounting the former and composed 
of ganglionic cells, the latter representing the cerebrum 
properly so called. 
The mass of cells which surrounded the intestine appears 
better circumscribed than in the previous stage; it has 
become concentrated into an elongated mass placed to the 
right of the intestine, and which, in its posterior part, presents 
some more voluminous cells. ‘This mass represents the 
common rudiment of the two genital glands, testis and ovary: 
its posterior part, containing the large cells, will form the 
ovary; and the large cells themselves are nothing but the 
ovules. 
The whole wall of the body is composed of an epithelium 
of considerable thickness, except at the level of the genital 
mass, where it consists of flattened cells. 
3. In the succeeding stage (fig. 5, not represented in the 
general figure) the nervous ganglion has definitively reached 
the summit of the bud; so that the change of form already 
indicated in the preceding stage is here completely effected. 
