1&07J Bitter. California Coast Ascidians. 3 



1. Depth, 2000 fathoms or more; number of stations, 7; number of spe- 

 cies, 3. 



2. Depth, 2000 to 1000 fathoms; number of stations, 9; number of spe- 

 cies, 3. 



3. Depth, 100 to 500 fathoms, 41; number of stations, 41; number of 

 species, 0. 



4. Depth, 500 to 1 fathoms; number of stations, 206; number of spe- 

 cies, 8. 



This gives Depth 1 : 1 species to 2 1-3 stations. 



Depth 2 : 1 species to 3 stations. 



Depth 3: species to 41 stations. 



Depth 4: 1 species to 251-4 stations. 



Of the 263 stations occupied only 16 produced ascidians. Two 

 of these, namely, 4420 and 4425, produced two species each ; 4420 

 was in a depth of 33 fathoms and 4425 in 1100 fathoms, both in 

 the vicinity of San Nicolas Island and both on sandy or muddy 

 bottom. Only three species were taken at more than one station, 

 Halocynthia okai coming from five stations, all in the Monterey 

 district, in less than 100 fathoms. 



The data are too few to permit of much in the way of general- 

 ization, but indications in two directions are rather strong. In 

 the first place, the off-shore ascidian fauna is considerably richer 

 south than north of Point Conception, so far as concerns the areas 

 worked over at this time ; and, second, that the deep water along 

 and just beyond the continental shelf is more prolific of this form 

 of animal life than is the shallower in-shore water. 



GENUS HALOMOLGULA. 



Test beset with processes each containing calcareous 

 spicules. Branchial membrane with nine folds on each side. 

 Infuiidibula present, large. Branchial stigmata small, irregular 

 in form and distribution, rarely with any curvature. One gonad 

 on each side of the body, the left in the intestinal loop. 



Halomolgula ovoida, n. sp. 



PL 1, figs. 1 to 6. 



Superficial Characters. Form varying from almost perfectly 

 spherical to strongly depressed biscuit-shape with elliptical base. 

 Outline in general very regular and even ; surface, except on area 



