100 University of California Publications. [ ZooLocy 
shaped; intestinal loop narrow, the anus situated on left side of 
the stomach. 
Testis rosette shaped, with about ten lobes; when fully ripe 
projecting prominently from the surface of the body on the 
ventral side, a short distance behind the proliferous stolon, which 
is between it and the endostyle; in younger zooids the testis not 
projecting thus from the body surface. The ovary, with its one 
large ovum, closely associated with the testes. 
Although I have decided, after much perplexity, to call our 
one species of Pyrosoma, P. giganteum, I must confess that the 
decision as between giganteum and atlanticum has little more 
value to my mind than it would have had it been made by throw- 
ing dice. Having no examples of atlanticum at hand for com- 
parison, I have been obliged to depend upon published descrip- 
tions of this species, and at almost all points at which authors 
make specifie differences between atlanticum and giganticum 
I find, among the large number of specimens at my disposal, 
agreements with both, and complete gradations from one to the 
other; in the case of the zooids, often within the same colony. In 
fact, I am compelled to question the actual existence of both 
atlanticum and giganteum as distinet species. For example, 
Savigny, 1816, was first to emphasize difference in form of the 
colony as being distinctive of the two species, he stating the 
atlanticum colony to be conical, and that of gigantewm ecylin- 
drical. This difference appears to have been chiefly relied upon 
by Herdman, ’88, ‘92, for distinguishing the two species. I find 
colonies that would certainly have to be described as cylindrical, 
and others that would as surely be regarded as conical. But 
there are numerous others, again, that the narrowing toward the 
closed end is so exceedingly gradual and ‘slight that to say they 
are conical would be no more apt than to describe the trunk of 
one of our tallest silver fir trees as conical. Again, as to the 
structure and arrangement of the test processes, I find, even in 
the same colony, essential agreement with those said by Seeliger, 
"95, to be characteristic for P. atlanticum var. tuberculosum; and 
at the same time with those described and figured by various 
writers for P. giganteum. 
