VAN NAME: SIMPLE ASCIDIANS. 453 
48. Phallusia prunum (Miiller), 1776. [Ascidiopsis complanatus Verrill]. 
Waters of northern Europe; Iceland; Greenland; Labrador and 
Banks of Newfoundland to Cape Cod, and slightly farther south at 
stations off the coast. 
Low water to 150 fathoms (commonest in shallow water). 
— . Phallusia inornala (Verrill), 1872. Uncertain species (not Hancock, 
1870) . Near Eastport, Maine (one specimen only) . 
12 fathoms. 
Family CIONIDAE Lahille, 1887. 
Genus Cigna Fleming, 1822. 
49. Ciona intestinalis (Linnaeus), 1767. 
Found in most parts of the world. On the American Atlantic coast 
occurs from the Gulf of Saint Lawrence to southern Massachusetts and 
Rhode Island, and still farther south at stations off the coast. Those 
from north of Cape Cod [= Ascidia tenella Stimpson, 1852] are said by 
Verrill to differ in external characters from those from south of Cape 
Cod [ = Ascidia ocellata Agassiz, 1850] and one or both forms may deserve 
recognition as varieties. Greatest depth recorded in New England 
region, 127 fathoms. 
The simple ascidians of this region cannot be as satisfactorily 
divided into northern and southern groups as the compound ascidians, 
for three of them range throughout the whole or nearly the whole 
region. These are: Bostrichohranchus pilularis, Tethyum molle, Den- 
drodoa carnea. Of the remainder, the following 23 are northern 
species whose range lies wholly or chiefly north of Cape Cod: 
Caesira septentrionalis. Tethyum coriaceum. 
" intumescens. " mortenseni. 
pannosa. " finmarkiense. 
citrina. Pandocia fibrosa. 
" papulosa. Dendrodoa aggregata var. pidchella. 
" retortiformis. " grossularia. 
Pyura echinata. Chelyosoma madeayanum. 
" ovifera. Corella borealis. 
" aurantium. Phallusia obliqua. 
Microcosmus nacreus. " prunum. 
Pelonaia corrugata. Ciona intestinalis var. tenella. 
Tethyum, rusticum. 
Nearly all of these forms either extend their range into the waters 
of northern Europe (some are circumpolar), or have very close Euro- 
pean allies. 
