PACIFIC TUNICATA OF U.S. NATIONAL MUSEUM 87 



thorax in specimens from B-8. Usually mantle of both thorax and 

 abdomen (more frequently on the latter) pigmented in brown or red- 

 dish brown. Branchial aperture 6-lobed, atrial aperture a round 

 opening, margined plainly and situated at level of second transverse 

 vessel. About 10 longitudinal muscles on each side of thorax and a 

 delicate transverse muscle across anterior part of branchial sac along 

 anterior margin of the first stigmatal row. A conspicuous, roundish 

 and dark purplish-brown pigment fleck at anterior end of endostyle. 

 Stigmatal rows 3, 8 stigmata in the first, 7 in the second, and 5 in the 

 last row. Tentacles 6, ciliated groove a small oval opening, dorsal 

 languets placed on left side along second stigma numbered from the 

 dorsomedian line. Anus opens at dorsoposterior corner of thorax with 

 two thickened lips. Proximal end of rectum considerably thickened. 

 Circumintestinal gland situated at level of middle of stomach and 

 consists of about three tubules. One testicular follicle, proximal part 

 of vas deferens coils 7 times at the maximum. 



Remarks. — The existence of zoochlorellae in the lacunae system is 

 unique and not known in any other forms of TridkleinnuTn. The prom- 

 inent superficial spiculeless layer may also be regarded as a signifi- 

 cant characteristic of the present species. The structures of test and 

 zooids of Trkl'ideimiUTii flanmn Sluiter, 1909, seem to resemble closely 

 those of the present species, although the existence of Zoochlorellae 

 is not described in the former. 



33. Tridideninuni viride (Hertlnian) 



Figure 29 



LeptocUnum viride Herdman, 1906, p. 340, pi. 8, figs. 28-33. 

 ? Didemnopsis globuliferum Sluiter, 1914, p. 76, fig. 17. 



MATERIAL EXAMINED 



Philippine Islands : Large Sibago Island ; W. R. Taylor, sta. r>. Two small 

 fragments (USNM 11646). — Baliwasan ; W. R. Taylor, sta. 10. Several colonies 

 (USNM 11649) ; one small colony (USNM 11659).— Cabaluay ; W. R. Taylor, sta. 

 14. Many colonies (USNM 11796). — Punta Natangol, Basilan Island; W. R. 

 Taylor, sta. 31. Many colonies (USNM 11661). — Kilay Island, near Langos 

 Island; W. R. Taylor, sta. 38. Five small fragments (USNM 11680).— Baluk- 

 baluk Island; W. R. Taylor, sta. 40. Many small colonies (USNM 11640).— 

 Boboh near Matanal ; W. R. Taylor, sta. 41. Four fragments (USNM 11672). — 

 Manicaan, 3 fath., sandy with sliort eelgrasses and little coral reefs; W. R. Ta.v- 

 lor, January 1941. Nine fragments (USNM 11642). — Amoyloi Reefs, southern 

 part of Basilan Island, 1-2 fath., sandy, stony, and coral reefs ; W. R. Taylor, 

 January 1941. Many colonies (USXM 11641) .—Basilan Island, Tundun Pasil 

 near lighthouse at Isabela Channel, 1 fath., rocky coral reef; W. R. Taylor, Jan- 

 uary 1941. Many colonies ( USNM 11681 ) . 



Description. — The present species seems to be very common in 

 Philippine waters, as there are abundant colonies in the material. 

 Most of the s])ecimens are rather small, even larger ones are only 30 

 mm. X 10 mm. or 24 nun. X 18 mm. in extent. Tliey are 0.5 mm.-l nun. 



