SOME PUGET SOUND ASCIDIANS. 605 



Chelyosoma producta Stimpson. 



Cliclyosonia producta Stimpson, '64, p. 161. 



Chelyosoma prodiictinn von Drasche, '84, p. 381, PI. VII. 

 Figs. 5-9. 



Chelyosoma prodiictinn Traustedt, '84, p. 7. 



Chelyosoma productum Herdman, '98, p. 252. 



Chelyosoma prodiictum Bancroft, '98. 



A large number of this very common Puget Sound species is 

 contained in the collection. 



Distoma molle n. sp. 



(PI. XX., Figs. 29 and 30.) 



General Character of the Colony: Comparatively reg- 

 ularly disc-shaped, attached by nearly the whole of the under 

 surface. Greatest diameter of the larger of the two colonies at 

 hand 8.6 cm.; shorter diameter of same colony 5.5 cm.: thick- 

 ness in thickest portion 2 cm. Very soft and flabby. Test more 

 than usually transparent, the individual zooids showing through 

 it very distinctly. Color, a light gray, this being imparted to 

 the otherwise quite transparent testicular mass by the thin, 

 somewhat more opaque superficial layer to which a small quan- 

 tity of fine sand adheres. The soft testicular substance contains 

 many cells which are small and rather uniform in form and size ; 

 no bladder cells present. 



General Character of Zooids : Distinctly seen through the 

 test for nearly their entire length. No systems recognizable. 

 Placed mostly at oblique but varying angles to surface of colony. 

 Each zooid in the form of a dumbbell with a very long handle, 

 the thorax forming one of the balls, the intestinal loop the other, 

 and the much elongated oesophagus and rectal portion of the 

 intestine the handle, the two ends or balls being nearly equal in 

 size. Average length about 8 mm., of which about 5 mm. be- 

 long to the handle of the dumbbell. The ectodermal appendage 

 at the posterior end of the abdomen large and always present. 



Branchial Apparatus : No orifices, either branchial or 

 atrial, recognizable on the surface of the colony ; this probably 



