242 



RITTER 



Braitchial apparatus. — Siphons short and small, in larger indi- 

 viduals almost entirely hidden by the tuberculation of the test, ob- 

 scurely four-lobed. Branchial tentacles about twenty, subequal in 

 length. 



Hypophysis mouth horseshoe-shaped, horns not rolled ; opening to 

 the left and toward the branchial siphon. Branchial sac with four folds 

 on each side, all of about equal prominence excepting No. 4, which is 

 somewhat larger. Formula for internal longitudinal vessels : 



Transverse vessels of three sizes. From five to seven stigmata to 

 the mesh. Endostyle narrow ; dorsal lamina a plain, low membrane. 



Digestive apparatus. — Stomach long and narrow, about twice as 

 long as thick ; somewhat curved, the concave side looking upward ; 

 having about fifteen longitudinal folds in its wall. Anus surrounded 

 "by a circle of about ten or twelve short thick knobs ; the terminal por- 

 tion of the rectum in the specimens examined narrowed down to a 

 thin neck. 



Gonads. — Two ovaries on each side, each a long, simple, tortuous, 

 cylindrical mass. Testis pouches scattered along these in the usual 

 way. Both sets of glands nearly or qviite ripe, but no tadpoles seen. 



Externally this species is very similar to S. joannce Herdman, from 

 Puget Sound (Herdman, 1899), but differs from it in having only two 

 in place of seven or eight ovaries on each side, and also in having only 

 one, in place of four, internal longitudinal vessels between the folds 

 of the branchial sac. Also it rather closely resembles S. pccssleri 

 Michaelson ^ from the region of Cape Horn from which it differs, how- 

 ever, in possessing fewer branchial tentacles, ^^55-/erz having sixty, and 

 in the prominence of some of the folds of the branchial sac ; in pcessleri 

 the first, or both first and second, are more or less rudimentary. 



Found on rocks at extreme low tide, Khantaak Island, Yakutat Bay, 

 June 31, 1S99. There are about fifty specimens of different sizes in 

 the collection. 



' Zool. Anzeiger, No. 560, 189S. 



