604 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
prominent siphons which are 11 mm. apart (measuring to centers of 
apertures) . The bod}^ is attached by the posterior end which extends 
into a rather narrow prolongation about 7 mm. long. The test is 
smooth and semitransparent; the branchial sac has intermediate 
papillae, and the alimentary' tract is large, the intestine being strongly 
curved and the rectum ascending close to the descending part of the 
intestine. 
Family CIONIDAE Lahille, 1887. 
Body elongated; branchial aperture regularly with eight lobes; 
atrial with six lobes. 
Conspicuous parallel longitudinal muscle bands on each side of 
the body. 
Tentacles simple. 
Dorsal lamina broken up into a series of languets. 
Branchial sac without folds, but with internal longitudinal vessels 
bearing papillae. 
Stigmata straight. 
Intestine largely posterior to the branchial sac. 
Reproductive organs in the intestinal loop. 
Genus Cioxa Fleming, 1822. 
This is the only genus of the family. It is of wide distribution but 
is very difficult to divide into well marked species, and recent writers 
treat most of those which have been described as merely synonyms of 
the well known and abundant European species Ciona intestinaUs (Lin- 
naeus) which is thus given an almost world-wide distribution. This 
solution of the question is, however, not entirely satisfactory, for the 
species certainly exhibits considerable local variation. 
The two species described from the New England region, C. tenella 
(Stimpson), type locality. Grand Manan, N. B., and C. ocellata 
(Agassiz), type locality. New Bedford, Mass., are among those which 
Hartmeyer (1903, 1909b) reduces to the category of synonyms of C. 
intestinaUs. In favor of this course the writer must admit that he is 
not aware of any anatomical differences separating tencUa and ocellata 
from the European intestinaUs or from each other, and that differences 
in external characters are very likely to be merel\' the direct effect 
of local conditions and not necessarily a proof of differences of race. 
On the other hand, though many specimens of both tenella and ocel- 
