1917] Eitter-Forsijtli : Aseidians of SoutJiern CaUfor)iia 463 



Zooicls. — Cylindrical, standing vertically in test ; length 2.5 mm., 

 width about 1 mm. ; length of languet and size of atrial orifice varies 

 depending upon position of zooid in system ; atrial orifice often wide 

 and gaping. Mantle thin, with feeble musculature, only a few circular 

 and longitudinal bands occurring near branchial and atrial orifices, 

 but pigment very abundant. Alimentary organs and stigmata easily 

 seen through mantle if some of pigment is removed with strong 

 alcohol (pi. 43, figs. 46 and 47). 



Branchial sustem. — Branchial orifices large and circular, pro.iect- 

 ing slightly above surface of colony. Branchial tentacles sixteen, 

 symmetrically arranged. Tentacles next to endostyle and lateral ones 

 at a cjuadrant's distance from this longest, with enlarged pigmented 

 bases, insertion deeper in the siphon than the others. Dor.sal tentacle, 

 inserted just above the hypophysis, long but its pigmented base not 

 as large as in the others; alternating with the major tentacles, four 

 tentacles about half as long; and finally alternating with the eight 

 large and medium-sized tentacles, eight very short ones (pi. 43, fig. 

 48). Twelve series of stigmata in the branchial sac with about four- 

 teen stigmata in a half-series; three internal longitudinal vessels on 

 each side; two or three stigmata in a me.sh except next to the dor.sal 

 lamina where there are from four to six. Dorsal lamina a plain 

 straight membrane, wider toward the posterior end of the body. Endo- 

 style large, conspicuous, straight. Neural gland situated over anterior 

 end of dorsal lamina just outside peripharyngeal band; duct of 

 gland opening conspicuouslv on surface of the oval dorsal tubercle 

 (/(2/., pi. 43, fig. 48). 



Digestive system. — Stomach (s., pi. 43, fig. 46) seeming to con- 

 sist of nine or ten large drawn-out loops, these being clustered at 

 esophageal end and from thence tapering back to pyloric end; loops 

 concentrated on right side, only three reaching around on left side so 

 that the latter presents a plain space from which a sac-like caecum 

 (c, pi. 43, fig. 46) is given off toward the intestine where it connects 

 with a pyloric gland located on that organ; posterior to branchial sac 

 and toward right side of body. Esophagus emerging from brauchial 

 sac at its posterior end near clorsal lamina ; about as long as stomach, 

 inserted into a depression surrounded by rounded ends of gastral 

 loops. Intestine on left side and posterior end of branchial sac, bend- 

 ing abruptly forward and dorsalward a short distance behind the 

 stomach ; anus on dorsal side of branchial sac about midway the length 

 of the zooids; two narrow, thin, non-pigmented strips on opposite 

 sides of intestine extend whole length of rectal portion. Rectum some- 

 what compressed, strips placed at edges of compression; strip along 

 outer convex side of intestine broader (pi. 43, fig. 46). 



Reproductive sijsteni. — One ovary and one spermary on each side 

 of posterior half of body, these appearing a.s conspicuous protuber- 

 ances, the .spherical ovary e.specially prominent when containing a 

 nearly mature ovum {o.. pi. 43, fig. 47) ; lobulated spermary anterior 

 to ovary of same side; ovary and spermary of left side farther forward 

 than tho.se of right. 



Habitat and distrihution. — The species occurs in great abundance 

 on piles, floats, etc., in San Diego Bay, but so far has not been taken 

 elsewhere, though it will undoubtedly be found at other points on the 

 coast of southern California at least. 



