1917] Eitter-Forsytli : Ascidiaiis of Soutlieni California 477 



Zooids. — Length about 1.5 mm.. consisting of thorax and abdomen 

 (pi. 40, fig. 21) ; long axis of abdominal loop usually continuous with 

 that of thorax, though often flexed laterallj' ; mantle adhering very 

 closely to test. A few ectodermal vessels (c.p., pi. 40, fig. 21) with 

 club-shaped extremities present just anterior to stomach and toward 

 ventral side of zooid, always in close proximity and just ventral to 

 budded branchial sac. 



Brancliial system. — Branchial orifice with six small pointed lobes. 

 Atrial orifice a great opening extending almo.st the length of sac and 

 reaching halfway across sides; atrial languet present, large and scoop- 

 shaped. Branchial sac with four series of stigmata each containing 

 eight stigmata in a half-series ; dorsal languets three, very slender. 

 Branchial tentacles very slender, about sixteen, of different sizes, not 

 arranged in any regular order. 



Digestive system. — Esophagus emerging from central portion of 

 posterior end of branchial sac, about one and one half times as long 

 as stomach, curved. Stomach smooth-walled, globiilar-elliptical. In- 

 testine consisting of a piece immediately following stomach, large in 

 diameter and about equalling stomach in length ; then a shorter con- 

 necting piece of smaller diameter, situated at lowest part of loop ; 

 next a large, smooth-walled, bulbous portion ; finally the rectal arm 

 of aboiit same diameter as esophagus, lying about parallel with 

 stomach and esophagus. The smooth-edged anus situated just opposite 

 middle of posterior series of stigmata. 



Reproductive system. — Testis {t., fig. 21) double, the two parts 

 forming rounded protuberances on right side of intestinal loop ; vas 

 deferens arising between lobes and running along side intestine, 

 vas deferens arising between lobes and running alongside intestine. 

 Ovary an elongated sac between stomach and rectum ; the small ovarian 

 eggs arranged in a row. It would seem that the ovarian sac allows 

 eggs to escape by rupture since in some colonies large eggs studded 

 the lowermost layer and apparently had no connection with zooids. 



Budding. — Intestinal and similar to that described for Diplosoma 

 pizoni. In this species esophagus of biidded sac joins mother zooid 

 very close to junction of mother esophagus and stomach. 



Habitat and disfrihiitio]!. — Known only from upper part of San 

 Diego Bay, near National City. 



The combination of characters in this species makes difficvilt its 

 inchision in any of the numerous genera that have been created for 

 ascidians of the Didemnum type. In fact, as the family Didemnidae 

 has been defined by .some authors, e.g., von Drasche (1883) and Van 

 Name (1910). it would be excluded from the family by its possession 

 of a straight vas deferens according to both these authors, and by its 

 atrial languet according to Van Name. We, however, agree with 

 Hartmeyer (1909) that the definition of the family ought to be suffi- 

 ciently elastic to admit this species. It seems to us that in the general 

 character of the colony, especially in its being hardened by the pos- 

 session of calcareous spicules and still more in the type of budding 



