78 University of Californa Publications. | ZOOLOGY 
under my observation the posterior process, when present, is 
directed somewhat to the right, with the atrial orifice turned cor- 
respondingly to the left; but this is quite surely correlated with 
the position occupied by the zooid in the salpa chain, and in half 
the individuals the process is probably situated to the left, with 
the atrial orifice to the right. Atrial orifice opening somewhat 
upward, but less so than the branchial. Lips rather prominent 
here also. 
Body muscle bands six, very broad and heavy. First and 
second interrupted dorsally, the first widely so, and all inter- 
rupted ventrally. First and sixth inclined strongly toward the 
middle of the body on both dorsal and ventral sides. <A single 
muscle in the anterior dorsal lip, but none in the ventral. <A 
few fibres entirely encircling the atrial orifice. First band 
bifureates on each side. Sixth band bifureates on right side (not 
shown in Fig. 21), but not on left, this being probably correlated 
with the fact that the post-body process is to the right side. (The 
asymmetry of this muscle in this species may be compared with 
that of the muscles of Cyclosalpa bakeri.) 
Endostyle relatively short, rather stout, somewhat curved to 
correspond with the gentle convexity of the ventral surface of 
the zooid; extending from within the prominent extension of the 
body in front of the branchial orifice to the posterior edge of the 
fourth muscle band. Gill likewise rather short, the anterior end 
being in the interval between the second and third muscle bands, 
and the posterior end at the nucleus on a level with the anterior 
edge of the sixth band. Hypophysis a considerable distance in 
front of the anterior end of the gill, narrowly elliptical, project- 
ing but slightly into the pharyngeal cavity. Ganglion situated 
at the immediate posterior end of the hypophysis. 
Nucleus small, ovoid, far back, not projecting from the gen- 
eral surface of the body. Embryos four, situated dorso-laterally 
in the interval between the fifth and sixth muscle bands. 
This is, from its rigidity and angularity, one of the best 
defined species of Salpa in our fauna. Though not abundant, it 
cannot be said to be very rare, since it has been taken at least 
eight times during the last three years, in no instance, however, 
in any quantity. 
i ee a ee 
