191"] Kitfer-ForsijfJi: Ascidiaus of Soutlicrn CaUfornia 481 



Zooids. — Consisting of thorax, abdomen, and pastabdomen ; thorax 

 a little longer than abdomen ; total length about 1 cm. ; long post- 

 abdomen terminating in an elongated granular mass, probably stored- 

 up nutrient material. Mantle very 1(hin with numerous delicate 

 longitudinal muscle bands extending entire length of animal ; circular 

 fibers in branchial siphon and a few irregular ones in mantle over 

 upper part of branchial sac. 



Branchial system. — Branchial orifice with sis blunt lobes; atrial 

 with flat truncated languet ending in three lobes (pi. 45, fig. 63). 

 Branchial tentacles about thirty, of three sizes. Branchial sac with 

 sixteen series of stigmata, from twenty-five to thirty stigmata in a half- 

 series; a small space near the endostyle free from stigmata; stigmata 

 next to endostyle smaller than others of a series. Endostyle straight 

 and narrow. Dorsal languets with flattened bases which run into 

 transverse vessels upon which they are situated, about as long as 

 stigmata in anterior part of the sac, becoming a little longer and 

 heavier toward posterior end of series. 



Digestive apparatus. — Esophagus emerging from middle of pos- 

 terior end of branchial sac, about equal to .stomach in length. Stomach 

 roughly cylindrical, a little longer than wide, with a seam on left 

 surface ; wall granular on its inner surface, but not folded. Intestine 

 extends posteriorly from stomach for a distance about equal to length 

 of stomach, then makes a loop and after running parallel to stomach 

 crosses esophagus on left side and ends in a bilobed anus less than 

 halfway up atrial chamber. In base of loop intestine narrows abruptly 

 to enter rectal arm between two blunt caeca (c, pi. 45, flg. 63). 



Reproductive system. — Gonad a pyriform elongated mass just 

 behind intestinal loop, the numerous testicular lobes composing the 

 great bulk of it ; usually one well-developed egg and several much 

 smaller ones, yellow in preserved specimens, situated in anterior of 

 gonad, surrounded by testis lobes. 



Habitat and distribution. — M. par-fustis is known from rocky 

 shores at La Jolla. Santa IMonica. and Pacific Grove; and from Dredg- 

 ing Station LIX. off' San Pedro, in twenty-eight meters water. 



Type locality. — La Jolla. 



The name is derived from Latin fustis. a cudgel. The systematic 

 position of this and the next species. 31. pellucidum, is by no means 

 clear. M. par-fustis might be placed in the genus Pasanvmaplidium, 

 its resemblance to P. retiform.e Herdm.. one of the species of this 

 genus with a smooth-walled stomach, being close. However, on the 

 basis of the single character, the sandiness of the test distinctive of 

 Psammaplidium, it would be necessary to assign par-fustis and pel- 

 lucidum to different genera, a course which in our judgment would 

 be unjustifiable in view of the very close resemblance of the two so 

 far as the zooids are concerned. 



All things considered, we conclude that MacrocUnum Verr. as 

 redefined by Hartmeyer (1903) is the generic group with which our 



