1907] Hitler. California Coast Ascidians. 11 



we seem to have about the opposite extreme of the type, namely, 

 variation in the direction of shortening the axis and concomitant 

 crowding together of the testis lobes. Again, M. arctica would ap- 

 pear to conform to the usual Molgula type as regards the liver. 

 But M. arctica has seven folds in the branchial sac, and, according 

 to Kiaer, a narrow anus "with a faint indication of four lobes 

 on the margin/' Whether, consequently, M. rcgularis shall be 

 regarded as more closely related to tenax or arctica will depend on 

 the ever-recurring question of the value to be placed on different 

 characters. There appears to be no particular prospect of reach- 

 ing a generally recognized standard of reference for the question. 

 The collection contained half a dozen specimens. Station 

 4309, Point Loma Light N.44, E. 8.6, March 3, 1904, 67-73 fath- 

 oms, bottom fine sand and shells. 



Halocynthia okai, n. sp. 



PI. 1, figs. 9 to 16. 



Superficial Characters. Nearly spherical, though some speci- 

 mens distinctly elongated antero-posteriorly. Attached by pos- 

 terior end, area of attachment usually small. Except on area of 

 attachment, tJtickly covered with long straight spines, these bear- 

 ing numerous small secondary spines. Each spine bearing a radial 

 tuft of from four to six or eight spinelets at its tip. In addition to 

 the long spines, numerous sessile whorled spinelets on the test be- 

 tween the bases of the large spines (pi. 1, figs. 9, 11, 12 and 13). 

 Siphons short and often so hidden by spines as to be found with 

 difficulty. Color brown to light gray. Length of largest speci- 

 mens, 80 mm. ; thickness of same, 55 mm. Length, of spines of 

 full-grown individuals, 10 mm. and more. Test strong and leath- 

 ery, rarely more than 1 or 1.5 mm. thick. Mantle rather thick, 

 not separating readily from the test ; mantle musculature consist- 

 ing of evenly-spaced bands radiating from each siphon, the cross- 

 ing of the two series giving the mantle the appearance of closely 

 woven cloth. The muscles extending over the entire body, but 

 somewhat weaker in the intestinal regions. 





