Notes on the morphology of the Tunicata. 589 



cord that in a number of instances I have found tadpoles of Ectein- 

 ascidia turhinata, in whicli the lens of the eye is composed of two 

 or three cells instead of one. Usually, of course, the lens is uni- 

 cellular. In those cases where two or three cells enter into its 

 formation, they are so pressed together as to form a single globular 

 body. (Cf. Plate 38, Fig. 65 a section of a tadpole of this species, 

 in which the lens of the eye is seen to be composed of two cells, 

 as indicated by the line running vertically through the globular lens.) 

 When the lens is composed of two or three cells, the contiguous sur- 

 faces of these cells are flattened, while their outer surfaces are rounded. 



3) Abreviated Development in Molgula pellucida Ver- 

 RILL ('?). 



In Casco Bay, Maine, attached to the "roots" of the kelp and 

 to the rocks or shells upon which the kelp grows, one finds many 

 small translucent Molgulas which seem to be M. x^ellucida. If these 

 are removed and are torn open in a watch glass one finds that they 

 contain embryos in difi'erent stages of development. The older of 

 these embryos show root-like processes like those which were de- 

 scribed by KuPFFER for the embryos of Molgula macrosipho- 

 nica^), and by Lacaze-Duthiers'^) for the embryos of an un- 

 determined species. I hope later to describe somewhat the ab- 

 breviated development in this form. I wish here merely to call 

 attention to the fact that we have on the American coast a species 

 of Molgula with no tadpole stage in its development, but, instead, 

 an embryo with peculiar root-like ectodermal processes which de- 

 velopes directly into the Ascidian without any free swimming period. 



KiNGSLEY has already shown that Molgula manhattensis has a 

 well developed tadpole in which similar root-like processes occur. 

 A comparison of the development of these two species should l)e of 

 interest. 



4) The Formation of the Periganglionic Membrane 

 in Cyclosalpa. 



In embryos and buds of Cyclosalpa pinnata the periganglionic 

 membrane and the membrane which separates the optic chamber 

 from the periganglionic blood sinus are formed by the apposition of 

 certain connective tissue cells which become very greatly flattened. 



1) KuPFFER, 1872. 



2) Lacaze-Duthiers, 1874, 



