VAN NAME: SIMPLE ASCIDIANS. 581 
Stomach always with a pyloric caecum; margin of anus smooth or 
with but two lips. 
Key to Species. 
1. Gonad branched. 
Gonad 3-branched. Body rounded or ovoid, attached by a small area. 
aggregata var. pulchella. 
2. Gonad unbranched, tubular and nearly straight. Body usually much 
flattened dorso-ventrally. One branchial fold on right side, none on left. 
Internal longitudinal vessels very few (only 4 or 5 on left side). . .cornea. 
Internal longitudinal vessels more numerous (a dozen or more on a side 
in large individuals) grossularia. 
Dendrodoa aggregata (Rathke), var. pulchella (Verrill). 
PI. 65, fig. 120-122; PI. 70, fig. 142; text-fig. 39. 
1871. Cynthia pulchella Verrill, Amer. Journ. Sci., ser. 3, vol. 1, p. 98. 
1872. Cynthia pulchella Verrill, Amer. Journ. Sci., ser. 3, vol. 3, p. 211. 
1879. Halocynthia pulchella Verrill, Preliminary Check-list of Marine Inverte- 
brates, p. 27. 
1879. Halocynthia pulchella Verrill, Bull. U. S. Nat. Mus., no. 15, p. 148. 
1879. Halocynthia pulchella Verrill, Proc. U. S. Nat. Mus., vol. 2, p. 197. 
1891. Cynthia pulchella Hcrdman, Journ. Linn. Soc. London, Zool., vol. 23, 
p. 586 (listed as uncertain species). 
1903. (Probably.) Dendrodoa aggregata (part) Hartmeyer, in Romer and 
Schaudinn, Fauna Arctica, vol. 3, p. 199. 
1909. Pyura aurantium (part) Hartmeyer, Bronn's Tier-reich, vol. 3, suppl., 
p. 1341. 
1912. Dendrodoa hukenthali var. pectenicola Michaelsen, Jahrb. Wiss. Anst. 
Hamburg, vol. 28, .suppl. 2, p. 132. 
Body of very regular form in most specimens, generally nearly 
globular or only a little higher or a little lower than broad. Attach- 
ment usually by a contracted area, sometimes by a short pedicel; 
apertures (both small and four-lobed) situated a little way apart on the 
region opposite to the point of attachment, either on low elevations 
or little if at all raised above the surface in the contracted specimens. 
Surface of body even, usually without deep folds, wrinkles, or adhering 
foreign matter, but with minute regularly disposed wrinkles, trans- 
verse and longitudinal, dividing the surface into minute, more or less 
square fields which become smaller near the apertures and are occu- 
pied by low irregular flattened elevations. These are occasionally 
so small, that the surface has merely a granular appearance to the 
naked eye, especially on the upper part of the body (near the aper- 
tures), but on the lower part they are coarser and their square outline 
