191"] Riitrr-Fofsijth : Asvidiaiis af SiintJiirn ('(iliforiiia 4()1 



Reproductive systejn. — Gonads hermaphroditic "polycarps, " those 

 on right disposed in row along the endostyle. as many as twelve in 

 large individuals; on left about five, situated near endostyle in ante- 

 rior half of sac {o. and t., pi. 42, figs. 36 and 37). In large individuals 

 peribranchial cavities contain numerous eggs and larvae. In such 

 eases the large oviduct forms a conspicuous portion of hermaphroditic 

 gonad {ov. d., pi. 42, fig. 38). A small tentacle-like sperm duct termin- 

 ates the male gonad near oviduct {v. d.. pi. 42, fig. 38). 



Habitat and distribution. — So far as known, only from wharf piles 

 in San Diego Bay where it occurs interwoven with hydroids and other 

 animals which inhabit the piles. The only specimens were taken in 

 June. 



Although the presence of eight internal longitudinal vessels on the 

 branchial sac is held to be a generic character in Polyzoa, we cannot 

 believe that the much smaller number in traiislucida ought to bar it 

 from the genus, so well does it agree with the other more important 

 generic characters. 



Botryllus tuberatus, n. sp. 



PI. 39, figs. 10 and 12; jil. 40, fig. 22 



Superficial characteristics of the colony. — Thin, encrusting, usually 

 not more than 3 or 4 cm. in expanse and 1 to 2 mm. in thickness. 

 Number of zooids in circular systems varies between three and ten ; 

 systems close together. Zooids usually black from pigment although 

 variations occur, and colonies with comparatively little pigment are 

 found. Zooids of a system communicate with common atrial orifice 

 by long, spout-like siphons {a.s., pi. 40, fig. 22) ; openings of siphons 

 varying from small and oval in younger zooids to large and gaping 

 in older ones ; edges of upper portions of openings unite to form the 

 common cloacal orifice, lower lips often extending a little beyond the 

 cloacal orifice, so as to be visible through it from above (pi. 39, fig. 12). 

 At intervals along margin of colony occur exceedingly dense, pedun- 

 culated bunches of ectodermal ampullae, each ampulla having its own 

 long ectodermal vessel running into body of colony ; young zooids 

 often occurring among the ectodermal ampullae {e.a. and y. z. pi. 39, 

 fig. 10) ; the ectodermal vessels generally branch and send out smaller, 

 less darkly pigmented ampullae. Test gelatinous and transparent. 



Zooids. — Length about .8 mm. General shape cylindrical but 

 curved, concave side being dorsal ; length a little greater than width. 

 Mantle strongly pigmented, and containing a few widely separated 

 extremely delicate longitudinal muscle fibers (pi. 40, fig. 22). 



Branchial system. — Sac cylindrical, a little longer than broad; 

 four series of stigmata ; three longitudinal vessels on each side ; about 

 fourteen stigmata in each half -series ; usually three stigmata in spaces 

 between longitudinal vessels and four between endostyle and its 

 adjacent vessels, and four between dorsal lamina and its ad.iacent 

 vessels; stigmata five or six times as long as broad. Endostyle wide 

 and straight. Dorsal lamina a plain membrane rolled into a tube. 

 Sixteen small branchial tentacles of which the eight larger ones alter- 

 nate with eight very small ones. 



