398 W. E. RITTER AND M. E. JOHNSON 
BRIEF DESCRIPTION OF THE SPECIES 
The species Cyclosalpa affinis (Chamisso) was taken in 
abundance at La Jolla from May to November, 1909, during 
which time most of the observational portion of this research was 
made. The longest chains and the largest wheels were brought 
in during the earlier part of this period, while the later catches 
yielded many specimens of the solitary form with short chains, 
and many medium sized single wheels. 
Although the salpae do not survive for more than a day or two 
in the ordinary aquarium, the material has been sufficiently 
abundant to admit of considerable work, with the living specimens. 
The two generations of this species differ markedly, as do those 
of all members of the genus. The intestine of the solitary form 
(fig. 11) is straight, extending nearly the full length of the animal, 
the anal opening being just back of the ganglion. The intestine 
of the aggregate generation, on the contrary, projects from the 
ventral side of the creature as a large, almost circular loop, (fig. 
12) the anus being only a little to the left of the oesophageal 
mouth. 
The solitary form has eight body muscle bands, according to 
our system of enumeration, while the aggregate generation has 
five on the dorsal and six on the ventral side. The hypophysis 
(hyp.), endostyle (end.), and gill (gi.) present much the same appear- 
ance in both forms. The orifices are also similar except that the. 
solitary form possesses short, tail-like appendages one on each 
side of the atrial orifice. Our records show the maximum length 
of specimens of the solitary generation to be 15 cm. and of the ag- 
gregate 8cm. In both generations the test is thin, soft, and highly 
transparent, without special thickenings. In the aggregate gen- 
eration, projecting from the ventral side, is the broad, thin pedun- 
cle (ped.) by which the zooids are united to form the wheel, and 
within the pharyngeal cavity on the right side, two thirds of the 
way back, is the embryo. In the young solitary individual, the 
eleoblast, near the heart, and the remnant of the placenta, about 
one-third of the way back from the oral orifice, are both opaque, 
nearly spherical bodies and are very prominent. 
