MM. Kowalevsky and Barrois on Anchinia. 11 
Taking as the longitudinal axis a line drawn from the gan- 
glionic mass to the pericardium, we can already recognize a 
general arrangement of the body analogous to that which 
exists in the adult; but we see that the part which lodges 
the genital mass is much more developed than in the adult, 
which causes the peduncle to be much nearer the upper part. 
Except for a slightly more advanced development, the 
internal organs are in the same state as in the preceding 
stage. The stomach has become narrower, and the intestine 
more elongated, which causes a notable alteration in the 
whole aspect of the digestive tube; further, the lateral parts 
of the cloacal sac have become elongated, so that already they 
surround the digestive tube and have come to communicate 
with the pharyngeal sac. 
The genital mass now presents a very perceptible division 
into testis and ovary (fig. 5) ; it appears disaggregated at its 
anterior part, thus giving origin to isolated cells, probably 
the same as those which afterwards occur around the intes- 
tine and which apparently represent the kidney. 
At the same epoch we begin to see distinctly the ciliary 
band (Zv) and the S-shaped muscle, which occupies nearly 
the middle of the body; further, the heart has been formed 
in the interior of the pericardium. 
4A (fig. 6, and fig. 1. 6-7). Later on the assimilation to the 
adult becomes easier and easier; nevertheless the posterior 
part corresponding to the genital mass still for a long time 
presents a very considerable development, producing a form 
quite different from that of the adult; lastly, the nervous 
ganglion has already ceased to occupy the summit of the 
body, and begins to pass towards the anterior side. 
The most remarkable change of this epoch consists in the 
formation of the branchial fissures between the pharyngeal 
sac and the lateral portions of the cloaca which cover its 
posterior surface. The branchial fissures are formed in a single 
line, and appear nearly all at the same epoch; nevertheless 
those of the middle are more developed than those of the 
extremities. They make their appearance at first in the 
form of small slightly elongated thickenings; and it is only 
subsequently and very gradually that they acquire the breadth 
which they afterwards present. 
The modifications previously described in the digestive 
tube have become more and more strongly marked at the 
epoch under consideration: the stomach has become con- 
siderably contracted, and the entire digestive tube has 
acquired the form of a bent cord which occupies a perfectly 
vertical position ; moreover the intestine has become greatly 
