igil] ASCIDIANS FROM THE COASTS OF CANADA. 1 25 



covered surface. Up to about 15 mm. in diameter. In addition to the 

 usual siphonal musculature, there are two circular bands (deficient ven- 

 trally) of short fibres on either side of the median plane. 



From 18 to 37 tentacles, the largest bi-pinnate. Aperture of dorsal 

 tubercle horseshoe-shaped; horns slightly inturned; opening between 

 horns directed backwards and slightly towards right side. Dorsal lamina 

 narrow, its margin smooth. Seven folds each side (in one specimen a rudi- 

 mentary eighth on right side dorsally). As many as 4 bars on a fold, on 

 the ventral side only. Stigmata forming the usual infundibula, each 

 stigma forming from ^ to ^ of a circle. An occasional small accessory 

 infundibulum between folds. 



Intestinal loop very narrow, bent into a semicircle, the concavity of 

 which is entirely filled by the left gonad. Anus with thickened smooth 

 margin. Gonads oblong, massive, with central ovary. Testicular lobes 

 massed along upper and lower sides of the ovary. Oviduct short, pro- 

 jecting upward from posterodorsal angle. Several (in one case 6) vasa 

 deferentia of medium length projecting inwards along the middle of 

 each ovary. Renal organ about equal in length to right gonad and of 

 the usual sausage shape. 



About 30 specimens from Departure Bay, Ucluelet, Alert Bay and 

 Hecate Straits. 



This form appears to be more nearly related to the following species 

 than to any other. 



C. hecateia sp. n. 



Rounded oblong, laterally flattened. Apertures rather close to- 

 gether on dorsal edge near anterior end. In the contracted condition, 

 they are at the bottom of a shallow furrow. Apertural lobes pointed. 

 Surface (except a narrow zone around each siphon) closely covered with 

 sand and fragments of shells. Up to 32 mm. in length, 20 mm. in depth 

 and 15 mm. in thickness. Musculature as in preceding species, but 

 the circular bands of fibres are more numerous (2 to 4 on each side) and 

 irregular. 



Probably about 35 or 40 tentacles, the largest bushily branched, 

 bipinnate or slightly tripinnate. Aperture of dorsal tubercle horseshoe- 

 shaped, directed toward right side. Dorsal lamina rather broad; its 

 margin incised, presenting about 7 large teeth or lobes, which are most 

 distinct posteriorly. It extends behind oesophageal aperture. Seven folds 

 each side. Up to 6 or occasionally 7 bars on each fold, on the ventral 

 side only. Stigmata as in last species, but the accessory infundibula are 

 more numerous. 



Intestinal loop narrow, horizontal, nearly straight. Gonads much 



