191''] Eitter-Forsyth: Ascidiaiis of Soutlicru California 



449 



Locality 



San Diego 

 Bay 



Pacific Grove 



Trinidad 



Northern 



Mendocino 



County 



Northern 



Mendocino 



County 



Patrick 's 



Point 

 Coronado 



Half Moon 

 Bay 



Point Con- 

 ception 

 Pebble Beach 



Length 



of 



bodv 



8 cm. 

 3.5 cm. 



2.5 cm. 

 2.5 cm. 



1.6 cm. 

 1 em. 



TABLE 1 

 Styela montereyensis 

 Length 



peduncle 

 19 cm. 



8 cm. 

 8 cm. 



Number of 

 branchial 

 Longitudinal vessels of sac tentacles 



( 7-14-10-16-13-16-9-SS-7 E. 133 



^ ) e-U-15-16-12-16-n-SS-7 L. 



end 



\ 6-13-9-11-7-14-8-17-6 R. 

 ) 6-lS-9-ll-8-lS-9-lS-e L. 



end 6-9-8-S-4-8-i-14-6 R. 



end 3-6-4-5-4-7-5-^0-3 R. 



3.5 cm. end 2-4-i-5-5-4-4-10-3 R. 



8 cm. end 3-7-5-S-5-8-5-1S-0 R. 



2.5 cm. end 3-4-5-6-3-4-3-8-2 L. 



2 cm. end 2-^-4-5-3-^-3-6-2 R. 



1.8 cm. end 2-7-3-:!0-3-7-3-J[^-3 R. 



1 cm. end 2-5-3-6-3-5-2-5-3 R. 



100 



Branchial sysUin. — Branchial tentacles numerous, long, .slender, 

 inflated, varying in size and number, maximum being about 130 (pi. 

 41, fig. 30). Atrial tentacles numerous, filiform, scattered over inner 

 surface of a velum near base of atrial siphon ; outer surface of velum 

 applied to wall of atrial siphon (pi. 41, fig. 32). Dorsal tubercle 

 prominent, hypophysis mouth of horseshoe type, varying greatly in 

 different individuals. Branchial sac with foiir fold.s on each side, those 

 next the dorsal lamina having the greatest number of longitudinal 

 vessels. Longitudinal vessels on folds and in spaces vary greatly in 

 number with size of individual. Transverse vessels cross longitudinal 

 vessels and prodiice the meshes which are about square. Number of 

 .stigmata in a mesh from three to ten. Dorsal lamina a plain mem- 

 brane. Endostyle tortuous at anterior end. Spinules occur on inner 

 .surface of siphons, their free margins rounded and their .surfaces 

 longitudinally striated (pi. 41, figs. 33 and 34). Each spinule a single 

 cell with a single nucleus situated .somewhat nearer the base than the 

 apex of the cell. The longer, more or les.s pointed striated part of the 

 cell is a thin, indurated layer making something like a shield on the 

 cell's back. The existence, in an animal as high in the animal kingdom 

 as the ascidians, of structures which consist of a single cell and present 

 differences in different specias, is a fact deserving special mention. 

 Huntsman (1911) wa.s the first to describe the spinules in detail, and 

 we are glad to be able to confirm his observation that the structures 

 are regularly different, at least as between S. montereyensis and jS. 

 yacutatensis. 



