VAN NAME: SIMPLE ASCIDIANS. 579 
unites P. libera with P. comata (see below). It is recorded from 
about Norway and Spitzbergen, in from 65 to 836 meters. 
A closely allied but distinct species is P. comata (Alder), 1863 (see 
also Alder and Hancock, 1905-1907, and Lacaze-Duthiers and Delage, 
1892), found on the French and British coasts. It has very few (gen- 
erally but one) internal longitudinal vessels on the interspaces be- 
tween folds, and a very narrow intestinal loop. Pandocia fibrillata 
(Alder and Hancock), 1907, is evidently also one of this group; the 
description and figures given are, however, very insufficient. 
Pandocia albatrossi, sp. nov. 
PI. 63, fig. Ill; -Pi. 64, fig. 113; PI. 70, fig. 146. 
The supposed Caesiras [Molgulas] from deep water mentioned by 
Verrill (1885a, p. 529) were mostly of this species, which in spite of its 
deep-sea habitat differs little from littoral forms. 
Body not attached, considerably flattened dorso-ventrally, so that 
it has an oblate spheroidal form. Orifices (both four-lobed) on very 
low conical elevations rather near together on the dorsal surface. 
Ventral portion of body covered with a thick growth of long tangled 
branching hairs to which fine sand, Globigerina shells, etc., adhere. 
These materials also cover the dorsal surface except close to the ori- 
fices. The ventral hairs are, however, not so long and numerous as 
in P. fibrosa. Largest specimens about 14 mm. long, the same in 
width, and 10 mm. in dorso- ventral diameter. Mantle musculature 
weaker than in P. fibrosa, the transverse and radiating bands narrower 
though more numerous, and the outer longitudinal fibrous layer less 
compact. 
Tentacles at least 40 to 50, of several sizes or orders. They are 
fewer, longer, and distributed with more approach to regularity 
according to the usual scheme (1,4, 3, 4, 2, 4, etc.) than in P. fibrosa. 
Dorsal tubercle small and difficult to distinguish; apparently 
simply C-shaped with a small open interval whose direction' is very 
variable in different individuals. 
Dorsal lamina a plain membrane, commonly found thrown into 
lateral undulations by the contraction incident to preservation. 
Branchial sac similar to that of P. fibrosa except that there are but 
two folds developed on each side, the first and third. The second 
and fourth are merely rudimentary, or absolutely wanting and their 
