igil] ASCIDIANS FROM THE COASTS OF CANADA. 1 29 



About 15 gastric folds. Apparently about 12 atrial tentacles. Up 

 to 10 or II tentacles grouped at anterior end beneath pharynx. A row 

 of testes on each side posteriorly and ventrally. In the right row there 

 are from 6 to 12 and in the left from 3 to 5. They are imbedded in the 

 test. 



Several colonies were obtained on the beach at Hope Island, by Rev. 

 Mr. Taylor in 1906. 



This form is doubtfully distinct from M. dura Ritter from Santa 

 Barbara, California. It differs from the descriptions of the latter, given 

 by Ritter and Michaelsen, in having a smaller number of oral tentacles 

 and a larger number of gastric folds. The differences in the reproductive 

 organs are probably referable to the greater maturity of the colonies 

 from Hope Island. 



M. taylori sp. n. 



This is a social species, the individuals being connected by stolons 

 alone. The largest individuals are 7X5X4.5 mm., in shape more or less 

 hemispherical. Apertures are transverse slits. The surface is smooth 

 or slightly wrinkled. The test is thin. 



The structure of the pharynx is the same as has been described for 

 the last species. 



Thirteen or 14 gastric folds. Atrial tentacles minute. In one individual 

 there were counted 1 1 ovaries, 9 testes on the right side and 1 1 testes on 

 the left. 



This form is so nearly identical in anatomical details with the pre- 

 ceding species, that one considers the possibility of their being different 

 forms of the same species, just as Ritter has considered that Perophora 

 annectens may form either social or compound colonies. With our present 

 knowledge we must consider this form distinct from M. dermatina, the 

 differences being, — 'social' instead of compound colonies, larger individ- 

 uals and colonies white instead of dark purple. 



Subfamily — Styelinae. 

 Genus, Katatropa nov. 



Syn. — Styela auct. part. 



Siphons with spinules. 



Four folds on each side, the second from above smaller than the first 

 or the third. Aperture of dorsal tubercle horseshoe-shaped, directed to- 

 ward left. 



Normally 2 gonads on each side, placed obliquely; the anterior ends 

 which bear the ducts, being directed downward tov/ard endostyle. Ovary 

 tortuous, rather short; testicular lobes grouped along either side of ovary, 

 little (if at all) branched; their long axes are perpendicular to plane of 



