142 Transactions of the Canadian Institute. [vol. ix 



one than that of the latter author. Savigny's Cyyithia dione, the type 

 of the genus Cczsira, doubtless belongs to this same group. His descrip- 

 tion of the oral aperture as being 4-lobed and of the dorsal lamina as 

 being smooth-margined was probably due to faulty observation. In 

 that case Ctenicella will be synonymous with CcBsira. 



C. littoralis (Verrill). 



Syn. — Molgula littoralis Verrill, Amer. J. Sc, ser. 3, vol. I, p. 56. 



Surface usually clean, at least in the neighbourhood of the apertures. 

 Few radicoid filaments on surface. Siphons quite variable in length, 

 usually rather short. Rows of papilla; on the outer surface of the 

 siphons, corresponding with the apertural lobes. The papillae are usually 

 small and few in each row. Nearly globular in shape, somewhat later- 

 ally compressed. Siphons on dorsal edge, nearer anterior end. 



From 20 to 30 bipinnate tentacles. Aperture of dorsal tubercle 

 curved, the horns usually approximated so as to form a circle; opening 

 between horns directed toward the right side. Dorsal lamina narrow, 

 not continued behind oesophageal aperture, its margin smooth. Seven 

 folds on each side, their posterior ends with smooth margins. Bars on 

 both sides of each fold, as many as 10 on a fold. Stigmata in the usual 

 infundibula (once branched), each stigma forming from % to yi 3. circle. 



Intestinal loop rather narrow, bent with the concavity dorsal. 

 Anus with smooth margin. Gonads in the usual positions close to in- 

 testine and renal organ. Ovary small, narrow; oviduct, which passes 

 from its posteroventral angle, is long and bent so as to form a right angle, 

 the terminal part passing up toward atrial siphon. Testicular lobes 

 variously disposed, usually ranged along the upper and lower borders of 

 ovary, sometimes forming a large mass covering the greater part of both 

 inner and outer surfaces of the ovary; the free portion of the single vas 

 deferens is of moderate length and projects from near the middle of the 

 inner surface of the ovary. 



A large number of specimens were obtained at low tide beneath 

 rocks and in the dredgings from stony and shelly bottoms. 



This form is very close to two European species, Molgula citrina 

 Aid. & Hanc. and M. echinosiphonica Lac.-Duth. The former has fewer 

 bars (6) and fewer tentacles (12 to 14). The latter has very conspic- 

 uous spines on the oral siphon whereas the atrial is smooth and the testi- 

 cular lobes are placed at some distance from the ovary. It is doubtful 

 whether these differences are important. 



C. pannosa (Verrill). 



Syn. — Molgula pannosa Verrill, Amer. J. Sc, ser. 3, vol. I, p. 55. 



Surface, except that of siphons, with numerous fine, long filaments 

 and entirely covered with shell-fragments, sand-grains &c. Siphons 



