Notes on the morphology of the f unicata. 587 



fluffy mass around the base of the branchial siphon , as in Mol- 

 gula manliattensis. 



There are no languets upon the dorsal lamina. 



The body wall is very thin and delicate with its muscles weakly 

 developed. 



There is a single, large, hermaphrodite gonad attached to the 

 mantle, on the left side, within the curve of the large, thin-walled 

 intestine. 



The oesophageal aperture' leads into a large stomach whose inner 

 wall is much plicated longitudinally. The large, thin-walled intestine 

 lies in a single loop on the left side, attached to the mantle and 

 enclosing the gonad. 



The ganglion (brain) is nearly globular and lies just above the 

 upper end of the dorsal raphe (cf. Plate 36, Fig. 36). 



The neural gland is ventral to the ganglion, lying in the en- 

 larged upper end of the dorsal raphe (cf. Plate 36, Fig. 36). It is 

 of large size, about eight times as large as the brain. 



Collected by Vinal N. Edwards, from soft mud, at a depth of 

 9 fathoms, in Buzzards Bay, near Wood's Holl, Mass. 



Section IX. 

 Brief Mention of certain Points of minor Interest. 



1) Cell Size and Body Size in the Ascidians. 



CoNKLiN has called attention to a remarkable agreement in the 

 size of the cells of the body in the large and in the small varieties 

 of Crepidula plana^ the different size of the two forms being due to 

 a difference in the number of the cells in the body, while corre- 

 sponding cells have the same size in the two varieties ^). Any one 

 who has occasion to study sections of a number of species of As- 

 cidians cannot fail to be impressed with the fact that in the smaller 

 species the cells seem disproportionately large; any organ, the ganglion 

 for example containing a much smaller number of cells than are 

 present in the same organ of a larger species, while the size of 

 the cells in the two species is much less different than is their 

 number. I have measured especially the nuclei of the smaller cells 

 in the brain and the cells in the neural gland of a number of species. 

 The size of the nuclei in the smaller ganglion cells is very nearly 



1) CoNKLIN, 1896. 



