Notes ou the inoii)bolo};y of the Tuuicata. 563 



the figure. These large ova are columnar with truncated inner ends 

 and rounded outer ends containing the germinal vesicle. In the inner 

 ends of these large egg cells we find numerous bodies which, from 

 their general appearance and reaction to stains, are seen to be cells 

 of the smaller sort from the ovarian wall, which have been ingested 

 by their larger sister cells, the ova. These can be found in all stages 

 of digestion, from the intact cell just taken in to mere masses of 

 granular debris, the remains of the nucleus, which digests more slowly 

 than the cell body. It is of some interest that these peculiar ova, 

 which have no investing follicle, still ingest the cells which lie near 

 their inner ends. The cells ingested are, of course, nascent ova, like 

 the follicle cells of the ordinary Tunicate ovum. 



The presence of large testes and large ovaries of this pecuhar 

 sort, in those colonies whose zoöids have lost their upper parts by 

 degeneration, suggests that this habit of degeneration may in some 

 way be associated with the processes of sexual reproduction. Not 

 having had opportunity to rear colonies of Leptoclinum and see all 

 the changes that occur I hesitate to discuss the point further. It 

 seems, however, clear that at the time when partial degeneration of 

 the zoöids occurs the colony is giving an unusual amount of nutriment 

 to the reproductive organs i). 



The whole matter of the nature and fate of the follicle cells in 

 Tunica ta has been much discussed. There is now pretty general 

 agreement that in the Ascidians the outer follicle cells are sister cells 

 to the ovum and that the inner folHcle is derived from the outer 

 follicle. The nature of the paranuclear bodies in Salpa I discussed 

 some time ago in a brief note in the Zoologischer Anzeiger -). I quote 

 this i)aper here in full, for the sake of comparison with the conditions 

 in the ovary of the Rat. 



Through the courtesy of Professor Brooks of the Johns Hopkins 

 University I have been enabled to examine a number of finely pre- 

 served embryos of several species of Salpa, and I desire after briefly 

 referring to certain points in recent papers upon Salpa embryology 



1) In the few colonies of Leptoclinum collected at two different 

 times in Woods Holl, Mass., I find no sign of degeneration. Among 

 the colonies collected later in Casco Bay, Maine, some are perfect and 

 others partially degenerated. All seem to be of the species which 

 Verrill has named Leptoclinum albidum. 



2) Metcalf, 18971. 



