458 University of California Publications in Zoology [Vol. IG 



Metandrocarpa michaelseni, n. sp. 



PI. 38, fig. 8; pi. 39, fig. 14; pi. 42, figs. 41-45 



Supfrficial characteristics (pi. 38, fig. 8). — Zooids appearing as 

 rounded mounds, the larger ones averaging about 4 mm. in diameter 

 through base and from 2 to 3 mm. high ; never embedded in a common 

 test but probably always a film of test passing between them ; adherence 

 to substratum, usually the under side of rocks, very close. Color 

 bright, cherry-red to hardly more than a tinge of that color ; cherry 

 far more common. Siphons short and always deeper red than body. 

 In large colonies, which may be half a square foot in extent, zooids 

 come to be close together, almost covering the substratum, but these 

 irregularly distributed with no intervention of common test. Blasto- 

 zoids seem always to move away some distance, three, four, five or more 

 millimeters and a delicate trail of test with a strand can be made out 

 connecting bud and parent {t.t.. pi. 39, fig. 14). Large, numerous 

 ectodermal vessels in test film around blastozoid {c.p., pi. 39, fig. 14). 



Zooids. — Test thick, tough, and not transparent, ilantle with 

 many circular and longitudinal muscle fibers. Body rests on its left 

 and ventral side with its anterior or disc shifted toward right and 

 dorsum so as to bring branchial orifice to top of mound (pi. 42, 

 fig. 42) ; length about 3 mm.; consisting of large branchial sac with 

 digestive and reproductive organs on the sides. 



Brancliial system. — Siphons fairly close together in central portion 

 of the upper surface of mound and very little elevated above general 

 .surface; orifices not bordered by definite lobes. Branchial tentacles 

 from thirty to forty, alternating long and short (pi. 42, fig. 43). 

 About twenty very small atrial tentacles (pi. 42, fig. 44). Branchial 

 sac at most with nine rows of stigmata; four or five internal longi- 

 tudinal vessels on each side ; largest individuals always with five on 

 each side; very fine transverse vessels cross most of stigmatie series 

 midway between the primary vessels. Much pigment in blood cells 

 throughout branchial sac as in other tissues of animal. Number of 

 stigmata about thirty in each half seri&s. Table 2 shows the distribu- 

 tion of the stigmata in five individuals. 



TABLE 2 

 Tndiv. Side 1st space 2d sp.Tce 3d space 4th space 5th space 6th space 

 ^ L. 6 6 6 5 3 5 ] 



; E. 6 6 5 3 3 



( L. 6 5 4 3 2 4 ] 



) R. 6 5 4 4 3 7 \ 



^ L. 7 6 5 4 5 ) 



] R. 6 4 3 4 2 6 ^ 



^ L. 6 5 4 4 4 ] 



) R. .5 6 3 3 3 4 ^ 



( L. 7 5 5 3 3 5 ] 



1 R. 6 .5 6 4 3 5 C 



D. L. 

 D. L. 

 D. L. 



Dorsal lamina, a plain fold growing wider and thicker posteriorly. 

 Hypophysis a single elliptical opening just anterior to the elongated 

 ganglion (liy. and g.g.. pi. 42, fig. 43). 



