454 University of California Publications in Zoology [Vol. 16 



gonads of the left side are as numerous as those of the right, though 

 in the form of the digestive tract and the number of the internal 

 longitudinal vessels the two are not widely separated. But in body 

 form, character of the external surface, and number of branchial ten- 

 tacles, as well as in the gonads of the left side, the two species are 

 sharply separated. 



Worthy of note is the fact that a majority of the Styelas having 

 a high number of gonads apparently belong to the Pacific Ocean. 

 But should more extensive study prove this to be actually so, the fact 

 could hardly be considered as anything more than a coincidence. So 

 far as we have been able to ascertain from the literature, the differ- 

 ence in thickness of the ovaries of the right side of S. harnkarti, as 

 shown in figure 39 of plate 42, is unique. It should be remarked that 

 it is not due to difference in the stage of growth in the ova, these not 

 being of recognizably different size in the larger ovaries. The mean- 

 ing of this difference is not clear, but the fact that on the right side, 

 where the number of ovaries is greatest, there are three distinct sizes, 

 the smallest being relatively quite small, suggests that these smaller 

 ovaries are in process of becoming rudimentary. 



We take pleasure in naming this interesting Stylea for Mr. P. H. 

 Barnhart, curator of the Seripps Institution, to whom we are indebted 

 for all the specimens so far seen. 



Ascidia californica, n. sp. 



PI. 38, fig. 6; pi. 41, figs. 24 to 27 



Superficial characteristics (pi. 38, fig. 6). — Elliptical in outline 

 but somewhat narrower anteriorly and quite depressed. Attached 

 b.y the entire left side. Test thick, gelatinous, containing many 

 anastomosing vessels, translucent but not sufficiently transparent to 

 permit much of the internal organs to be seen ; surface generally 

 smooth and even. Siphons usually not prominent; the branchial 

 directed forward and frequently somewhat to the right; the atrial 

 located at half or a little more than half the animal's length toward 

 posterior end on the upper stirface but toward the left edge. The 

 eight lobes of the branchial orifice are regular and somewhat long and 

 pointed, with a brick-red pigment spot between the lobes. Lobes of 

 the atrial orifice, almost invariably six in number, are bordered by a 

 series of minute teeth ; shorter and more rounded than the branchial 

 lobes and similarly possessing pigment spots (p.s., pi. 41, fig. 27). 

 Largest specimen about 3.5 cm. long and twice as long as wide ; usually 

 smaller. Jfantle thin and transparent on left or under side, with no 

 muscle bands except in siphons and anterior part of brancliial sac ; 

 on right or upper side muscle bands, running in all directions, form a 

 thick pad. 



