Miscellaneous. 311 
reservations as to its homology with the sand-canal of the other 
Echinodermata. 
The peduncle of the young animal contains six cellular cords— 
one central and five forming around the central cord the edges of a 
pentagonal prism, the axis of which it would occupy. The central 
cord is prolonged into the inflated part of the body, in such a way 
as to occupy the axis of the spiral formed by the digestive tube, 
and its cellular walls become thickened so as to form an ovoid body, 
the large cells of which, in sections, are always arranged in two 
contiguous series, so that the ovoid body is filled up. This body is 
surrounded by a fibrous envelope, and becomes united at its upper 
part with the wall of the pharynx. It occupies exactly the same 
position, relatively to the digestive tube, as the sand-canal of the 
Sea-urchins. 
The five cords which surround the axial canal are slightly in- 
flated at their entrance into the body properly so called; a cavity 
makes its appearance in their inflated region; from this results the 
formation of five chambers, which constitute the first trace of the 
chambered organ. Cellular buds, starting from the apex of these 
chambers, soon arrive, by creeping along the walls of the body, at the 
cireumbuccal canal ; the latter forms a bud at the point of meeting ; 
the two buds then bear towards the exterior; the wall of the body 
forms a sort of cap for them, and all these parts, increasing in size 
together, finally constitute an arm. The five arms do not make 
their appearance simultaneously, but successively, and still continue 
to show great difference of size during nearly the whole duration 
of the following phase. Their growth is executed from the com- 
mencement as indicated in our communication of the 16th July. 
2. The Pentacrinoid phase extends from the appearance of the 
arms to the complete-formation of the cirri. At this moment, in 
consequence of the development of the arms, the oral surface of the 
larva, which was at first entirely occupied by the tentacular ring, 
has become considerably enlarged, and the anus has been shifted 
into it; it opens henceforward at the apex of a special tube. This 
surface is cut up into five sectors by the tentacular canals, which 
run towards the anus. Upon each of these sectors there is seen a 
hydrophorous orifice, resembling the single orifice of the preceding 
phase, and to each of these five orifices there corresponds a hydro- 
phorous tube. In sections these five tubes appear to terminate by 
a free extremity in the general cavity ; but we have reason to think 
that these tubes are normally in continuity with tho five canals 
which traverse the wall of the body to terminate at the five hydro- 
phorous orifices. 
The ovoid body which traversed the axis of the general cavity has 
now the aspect of a double canal, the two parts of which seem to open 
into the pharynx, a point, however, which still needs further investi- 
gation. The chambered organ has acquired very nearly its definitive 
form. At its level, in those individuals of which the arms are not 
yet much developed, we see originate from the central peduncular 
