Yerrill on Ascidians from New England. 



Art. XLIV. — Brief Contributions to Zoology from the Museum of 

 Yak College. No. Xlll.— Descriptions of new and imperfectly 

 Jcnoivn Ascidians from New England] by A. E. Veeeill. 



Family, Polyclinid^. 

 I glabrum Verrill, sp. nov. Figures 20 to 22. 

 When young (fig. 20) this species forms small, clavate, or tur- 

 binate, translucent masses, attached by a narrow base, and con- 

 taining only a few animals arranged somewhat irregularly around 

 20. 21. a single cloacal opening. Thesur- 



i^^ *^^^^t^ face is smooth and glabrous, witli- 



W ^^^^^^ out adhering sand ; the texture is 

 W ^^^^^m^^ rather firm, but so transparent as to 

 r^f?F ^ ^ T^ ^^ ^^ distinctly show the animals, which 

 -== ^^.^ elongated and comparatively 

 large, standing nearly vertically, with the ovaries extending 

 nearly to the base of the mass. The intestines, filled with pellets 

 of foecal matter, appear as conspicuous, dark, obhque spots. 



Larger specimens (fig. 21) become "5 to 1 inch or more broad 

 and have a large attachment and expanding sides, with a more 

 22. or less irregular, smooth upper surface, whicli 



> is usually slightly convex. Several cloacal 

 openings are irregularly placed on the upper 

 '■ surface, and numerous individuals are irreg- 

 ularly scattered throughout the mass, though 

 often forming rather indistinct circular groups 

 around the apertures. The surface is glabrous 

 and the tissues translucent, as in the younger 

 specimens. ^ , . 



The animals, when mature, are mostly aboui 

 •20 of an inch long, and about "05 in diameter, 

 but many are '25 of an inch long and wj 

 •07 in diameter. The thorax is longer ana 

 broader than the abdomen, and m specimen 

 taken about the middle of August the cloacai 

 chamber was distended by three to five la « 

 . eggs, with the tadpole-shaped embryos ne^^ 

 developed, while the post-abdomen was q 

 slender and the ovaries shrunken. ^Vf']^'^ 

 earlier (fig. 22) had the post-abdomen much thicker ^^^ 

 ^ ' 'irge ovaries, in the upper part^of whicn , 

 stages of growtl 



the upper part of which we 

 vth, while the cloacal chamber 



