VAN NAME: SIMPLE ASCIDIANS. 477 
locality); Beesley's Point, New Jersey; the mouth of Patapsco River, 
Maryland; and Beaufort, North Carolina. 
Although the Yale collection contained specimens of ascidians 
from various stations to depths of 85 fathoms labeled " Molgula man- 
haitensis" those from deeper water proved on dissection to be of other 
species, and as far as the writer can ascertain from the series of speci- 
mens available, this species is confined to shallow water, 16 fathoms 
or less, and it is certainly most plentiful in the shallowest situations. 
Along the coast of southern New England (as far north as the 
vicinity of Boston), Long Island, New Jersey, and doubtless also farther 
southward, this is the most abundant and conspicuous of the simple 
ascidians. This great abundance is largely due to its habit of growing 
upon eel-grass (Zostera) as well as attached to stones, piles of wharves, 
etc., for the extensive shallow flats on which a luxuriant growth of the 
above mentioned plant develops every summer in the bays and 
harbors of these coasts, afford almost unlimited opportunity for the 
increase of an animal adapted to that particular environment. In 
favorable situations it grows in clusters of several or many individuals 
of different sizes. This species has been the subject of a number of 
anatomical and embryological studies. 
Tellkampf (1874) published some notes on the distribution, anat- 
omy, growth, and development of this species, which, however, re- 
quire some correction. He stated that the branchial sac was not 
plicated, and supposed that this species developed with an alternation 
of generations, the eggs developing into a so called "Mammaria" 
instead of into the parent form. Just what this "Mammaria" was, 
is difficult to say. His description somewhat suggests a young 
colony of the genus Botryllus. 
Kingsley (1882) also made a study of this species, and flatly denies 
that any such alternation takes place, saying that the tailed larvae 
develop into the adult in the usual manner. 
C. ampulloides (Van Beneden), 1846, widely distributed in the 
waters of western and northern Europe and Asia, and recorded also 
from Greenland, is a littoral form closely allied to C. vianhattensis, 
and C. socialis (Alder), 1863, is also a closely allied western European 
form. Through the kindness of Dr. Hartmeyer the writer has been 
enabled to make a direct comparison of specimens of these species with 
C. manhattensis, but is not inclined to regard the European species 
as identical with each other or with C. manhatienms . Of the two 
