192 Mr. A. Hancock on the Anatomy of the 
of the egg and the hatching of it, and the subsequent growth of 
the young polype has been minutely investigated by Sir J. G. 
Dalyell. But the generative organ remained unrecognised until 
it was pointed out by Professor Allman. The appendage to the 
lower extremity of the stomach, considered by Trembley to be 
muscular, Professor Allman believes to be an ovary: that it is 
so there can be no doubt, as eggs may occasionally be seen in 
connexion with it. Appendages of this kind exist in Alcyonella, 
Plumatella, Frederiéella and Paludicella, and will probably be 
found in all Ascidian polypes. In Plumatella and Fredericella 
there are however three of these appendages or filaments, Pl. IIT. 
figs.4f,d,d, & 5 e,ée,h,h, which are all attached to the lowest part 
of the stomach, and passing down have their other ends attached 
to the wall of the cell not far from the insertion of the polype-re- 
tractors. It is difficult to say whether all three are connected with 
the generative function, or whether some of them are not muscles 
for the retraction of the stomach. A bundle of such retractors 
has been described by Dr. Farre in the marine species, attaching 
the inferior end of the stomach to the base of the cell; but one 
of them is generally thicker than the rest, and may probably be 
connected with the reproductive system. Paludicella has two 
such filaments; one, Pl. IV. figs. 1 & 7 n, g, passing in the usual 
manner from the lower end of the stomach ; the other, m, d, from 
the upper. ‘These two filaments are mserted upon the posterior 
wall of the cell, one a considerable way above the other. When 
the polype is retracted these insertions are found to be a little 
above the gastric attachments, and the filaments, fig. 2 7, k, 
doubled upon themselves. These are thick, cylindrical and ap- 
parently tubular, and do not at all resemble muscles, and indeed, 
from the relative position of their attachments, they seem ill 
adapted for retraction. 
In Plumatella and Fredericella, one, P\. III. figs. 4d, d& 5 e, é, 
of the filaments is generally stouter than the other two, and this 
has frequently an egg, e, f, attached to it. When the ovum is 
much developed, it is difficult to make out its relationship to the 
filament or ovary; but when quite young, it has all appearance 
of originating from the interior. On one occasion | observed two 
eggs in connexion with the ovary, one almost mature, the other 
only forming. The former, fig. 5, was attached rather below 
the middle of the generative organ. When the polype was pro- 
truded, this organ dragged forward the upper end of the egg; 
the other end of it was then seen to be attached to the wall of 
the cell by the continuation of the filamentous ovary e’. A little 
below the egg there was a slight oval swelling, in the interior of 
which was seen a nucleated cell, g, undoubtedly an ovum in a 
very early stage of development, and apparently in the interior 
