No. 2.] SOME BERING SEA TUNICATES. 8 1 



Unfortunately, the collection does not contain sufficient speci- 

 mens of this species to enable me to answer several questions 

 of fact that arise from a consideration of the observations pre- 

 sented. However, the facts that we have scarcely admit of 

 misinterpretation. When the post-abdomen first becomes free 

 from the parent zooid, the ovary contained in it has a large 

 number of ovarian ova in various stages of growth. That some 

 of these mature, become fertilized, and develop into tadpoles 

 is proved by direct observation. When the full tadpole stage 

 is reached, only a very limited number of individuals — ten to 

 sixteen — is present in each cavity, and the cavities contain 

 nothing else than the tadpoles." The ovarian ova are distinctly 

 amoeboid in form and certainly contain ingested cells. The 

 conclusion seems inevitable that by far the larger portion of 

 the ova of each ovary are consumed as food by the few of the 

 same ovary that develop into embryos ; furthermore, that the 

 granular material (food yolk) of the parental mesenchyme cells 

 is also made use of as food by the growing embryo, and that 

 probably other tissues of the parent zooid are used, to some 

 extent at least, in the same way. 



The absence of follicular epithelium and " test " cells from 

 the ovarian ova is undoubtedly correlated with the amoeboid 

 nature of the ova ; but it is quite possible that their absence 

 is more apparent than real. Some of the cells ingested by the 

 ova may represent either follicular or "test" cells, or both. 

 The observations also seem to indicate that the test, or " cellu- 

 lose mantle," of the late embryos and tadpoles engulf various 

 portions of the parental zooids, and this suggests that the 

 embryos are in some way nourished by this means. Such 

 a process, however, would be quite remarkable, and further 

 observations on the point are greatly to be desired. 



University of California, February lo, 1S98. 



