PACIFIC TUNICATA OF U.S. NATIONAL MUSEUM 153 



(1) 2^ (1) 2-4 (1) 3-5 V. Only two tentacles in newly formed young 

 zooids (lig. 5dd), but at least four in larger old zooids. Anterior 

 margin of intestinal loop reaches middle of fourth stigmatal row or 

 third transverse vessel ; anus opens at level of third transverse vessel. 

 Posterior half or two-tliirds of stomach located posterior to rear end 

 of branchial sac; 7-10 longitudmal plications on stomach surface, 

 besides typhlosolis. 



75. Botryllus magnicoecus (Hartmeyer) 



Figure CO 



BotryUoldcs nigrum var. muijiiicoceum + Sarcohotrylloides raccmosum Hart- 

 meyer, 1912, p. 271, pi. 41, fig. 11 ; p. 274, pi. 37, fig. 5 ; pi. 41, fig. 9. 



Botryllus magnicoecus Michaelsen, 1921, p. 6, pi. 1, figs. 1-4. — Michaelsen, 1923, 

 p. 50.— Hartmeyer & Michaelsen, 1928, p. 331.— Hastings, 1931, p. 79, fig. 5. 



Polycyclus rufus Oka, 1927b, p. 608. 



Botryllus rufus Tokioka, 1953a, p. 240, pi. 2, fig. 5 ; pi. 43, figs. 4-7. 



MATERIAL EXAMINED 



China : Probably Amoy ; received October 12, 1932, from T. Y. Chen, Univer- 

 sity of Amoy; sta. 1, no further data, one colony (USNM 11532) ; sta. 9, no 

 further data, two colonies (USNM 11531). 



Description. — Three colonies were examined, the largest is 33 mm. 

 X15 mm. in extent and 11 nun, in thickness. Colonies irregularly 

 lobate, dark purplish upper layer containing zooids, lower layer trans- 

 lucent, milky white. Test white. Surface free from foreign matter. 

 Very distinct stellate systems, each consisting of 4-11, most fre- 

 quently 6-9 zooids. Many whitish ampullae are seen between these 

 systems. Zooids rather small, less than 2 mm. in length, situated 

 perpendicularly. Mantle deep purple but may fade to yellowish 

 brown. In branchial sac 9-11 stiginatal rows on right, 10-12 on left 

 side. Second row reaches midline dorsally ; last row usually rudimen- 

 tary. Stigmata arranged (D=dorsal, V=ventral) : D 5-G (1) 2-3 

 (1) 2-3 (1) 3-5 V. Tentacles 8, larger and smaller ones alternate 

 regularly (fig. 606). Ciliated groove an oval orifice (fig. 60c). 



Distal branch of first intestinal loop covers posterior two or three 

 stigmatal rows so that anterior margin of loop reaches tenth to sev- 

 enth transverse vessel. Second intestinal loop very shallow, axis 

 passes through cardiac half or cardiac end of stomach. Anus attached 

 to branchial sac at level of sixth or seventh transverse vessel and opens 

 at level of fifth or sixth transverse vessel; margin plain. Hind stom- 

 ach faintly constricted from following part of alimentary canal. 

 Stomach quite posterior to branchial sac with 13 longitudinal plica- 

 tions, including typhlosolis, on surface. Pyloric caecum very distinct. 

 Testis situated roughly at level of seventh transverse vessel or eighth 

 stigmatal row near middle on each side, usually right testis located 

 slightly more anterior than left one, approximately for distance of 

 one-half stigma length. Testis consists of three lobules (fig. (iOd) in 



