No. 3-] BUDDING IN PEROPHORA. 403 
familles d’Ascidies composées (Clavelinidae, Perophoridae, Bo- 
tryllidae, Polyclinidae, Distomidae, Didemnidae, et Diplosomidae) 
lorgane vibratile débute par un tube aveugle, formé par un 
diverticule de la vésicule endodermique primitive”’ (/.c., p. 131). 
The Sexual Organs. 
My observations on the development of the sexual organs 
have not been carried beyond quite an early stage, but, so far 
as they go, they closely agree with the description given by 
Van Beneden and Julin (33) for the buds of Perophora listert. 
Shortly after the peribranchial cavity has been completely 
divided off from the branchial sac, a small collection of cells 
appears between the two arms of the U-shaped digestive tract, 
and at the level of the duct of the “‘organe réfringent,” almost 
at the point where the latter is connected with the stomach. 
The sexual organs arise from this little spherical mass of cells, 
which are at first but loosely held together and identical in 
appearance with the amoeboid cells of the blood. Pl. XXXII, 
Fig. 32, a, which is precisely similar to Van Beneden and 
Julin’s Pl. XVI, Fig. 5, 4, shows the intimate relation between 
the cells of the blood and those ofthe rudiment ( g.7.), so that 
there can be no doubt that the two are identical. The connec- 
tion, already described by the Belgian authors, of some of the 
peripheral cells of the mass with surrounding blood cells by 
protoplasmic processes is distinctly seen in the figure at mc. 
A small, irregular cavity (¢.g.7.) is also shown in the center of 
the clump of cells. Some of the free cells lying above the 
rudiment (Fig. 32, a, g.c.) are seen to be spindle shaped; these 
soon become joined, end to end, to form a solid cord, united at 
one end to the spherical mass of cells and taking a course 
parallel to that of the intestine (Fig. 32, 0, g.c.). This figure 
represents a later stage, in which the cavity is considerably 
enlarged and the genital cord (g.c.) is present as a solid single 
row of cells (cf. Pl. XII, Fig. 2, of Van Beneden and Julin). 
A furrow, which appears opposite to the attachment of the 
cord, now divides the hollow sphere into two lobes, the cavities 
of which are not completely separated, but remain in communi- 
