1917] Eitter-Forsyih: AsckUans of Southern California 475 



ing test. Muscle fibers in transverse vessels and two strong bands on 

 each side of dorsal lamina coalescing at posterior end of branchial 

 sac into a band that continues posteriorly through test strand nearly 

 to lower surface of colony. A few ectodermal vessels with enlarged 

 extremities present on ventral side of zooid in angle between sac and 

 intestine {e.p., pi. 43, tig. 50). 



Branchial system. — Branchial siphon plainly 6-lobed; atrial orifice 

 a great opening usually longer than half the branchial sac and ex- 

 tending at least halfway across sides of sac. Branchial sac with four 

 rows of stigmata, each containing seven or eight large stigmata in a 

 half-series. Three tentacle-like dorsal languets. Branchial tentacles 

 sixteen, of three sizes, and symmetrically arranged so that the four 

 largest alternate with the four or second size and finally the eight 

 smallest alternate with the eight larger ones. 



Digestive system. — Intestinal loop twisted and turned up at a 

 right angle to long axis of zooid so that reproductive organs, belonging 

 typically to right side, become located at posterior end of zooid. Short 

 esophagus given off from posterior dorsal pai-t of branchial sac ; 

 stomach globular, smooth-walled ; portion of intestine immediately fol- 

 lowing stomach and about equaling it in length connected by a piece 

 of less diameter to a rigid bulbous portion at beginning of rectal arm ; > 

 rectum oblique ; anus situated less than half the distance up branchial 

 sac. Pyloric gland (p.j/L, pi. 45, fig. 68) and its bulbiferous duct 

 well-developed. 



Reproductive sijstrm. — Situated on right side of intestinal loop, 

 but bend of intestine brings gonad to posterior of zooid. Testis 

 conical, two-lobed, the vas deferens emerging from between the lobes. 

 Ovary usually containing one large egg and a few small ones (o., pi. 

 43, fig. 50). Ripe discharged eggs and embryos scattered thickly on 

 lower layer of test, the eggs apparently making their way down 

 through the strand of test to reach this position ; eggs observed at dif- 

 ferent levels in these strands seeming to support this theory (oc, pi. 

 •.44, fig. 50). Tadpoles probably break through test and escape into 

 common atrial cavity and pass out through common atrial openings. 



Habitat and distribution. — Known only from San Diego Bay where 

 but a single colony has yet been taken, this having been found on piles. 



D. pizoni is undoubtedly vm-y close of kin to D. lisfcri. but there 

 is hardly a doubt about their specific distinctne.ss. Listeri has bladder 

 cells in the tests; pizoni has not. Listen has ten stigmata in a half- 

 series, while pizoni usually has seven and seems never to have more 

 than eight. The stomach of pizoni is more spherical than that of 

 listeri, it being figured as heart-shaped in the European species. 



Asexual reproduction in D. pizoni. — The larva of this species pre- 

 sents the same aspects as those pictured and described by Salensky and 

 Caullery for Diplosoma listeri. In the diplosomic larva the zooid 

 and blastozooid are distinguishable here as there, the former being 

 characterized by its vascular appendages and pigmented larval sense 



