80 UNITED STATES NATIONAL MUSEUM BULLETIN 251 



30. Trididemnum savignii (Herdman) 



FiGUBE 26 



Didemnum savignii Herdman, 1886, p. 261, pi. 34, figs. 1-5. 

 fDidemnum arcolatum Herdman, 1906, p. 337, pi. 8, figs. 26-27. 

 Trididemnum savignii Hastings, 1931, p. 91. — Van Name, 1945, p. 100, fig. 45; 

 pi. 18, fig. 4.— Tokioka, 1953a, p. 197, pi. 21, figs. 4-8. 



MATERIAL EXAMINED 



Japan : Honshu, off Noma Saki S.86°E, 5.7 mi. ; Albatross sta. 3725. Two 

 colonies (USNM 11772). 



Philippine Islands : Off Jolo Light east 2.6 miles ; Albatross sta. 5174. One 

 colony (USNM 11733) from the surface of Stolotiica styeliformis Van Name 

 (USNM 11634) which was attached to gorgonian coral, Echinogorgia sp. (USNM 

 52052). 



Palau Islands : Barrier reef 8 mi. NW. of Koror Island ; GVF sta. 25. Six 

 colonies (USNM 11388). — Fringing reef of small island in lagoon of Eil Malk ; 

 GVF sta. 252. About 10 small, nearly spherical colonies (USNM 11429). 



Marianas Islands: Saipan ; P. E. Cloud, sta. D-8. One small colony (USNM 

 11468) from the basal part of Eudistoma angolanum (Michaelsen) (USNM 

 11504). 



Hawaiian Islands : Off Mokuhooniki Islet between Maui and Lanai ; Alba- 

 tross sta. 3872. One small, elliptical mass (USNM 11779). 



Description. — One small colony each from the Philippines, the 

 Hawaiian Islands, and Saipan Island, as well as 2 colonies from Japan 

 and 16 small pieces from the Palau Islands were examined. Among 

 these colonies, only the Japanese specimens are large and massive, 

 35-45 mm. X 30 mm. in extent and 20-30 mm. in height and each con- 

 sists of several mammillary processes (fig. 26). A roundish common 

 cloacal aperture opens at the distal end of each process, the spacious 

 hypoabdominal lacunae are well developed at thickened portions of 

 the colonies and the axial portion of the colony beneath these lacunae 

 is occupied by well-defined core matrix. The distal parts of mam- 

 millary processes are red, other parts are grayish j^ellow brown. As 

 the preservative is dark yellow, the whole colonies might have been 

 reddish orange when alive. Other small colonies from various lo- 

 calities vary considerably in color, from white or faint milky white to 

 brown. Test soft, gelatinous, translucent, or quite transparent in the 

 colonies which are rather sparsely impregnated with spicules. Super- 

 ficial spiculeless layer distinct, not thick. Ilypozooidal lacunae well 

 defined, but never harbor zoochlorellae withm. Spicules compara- 

 tively large in colony from Hawaiian Islands (31-40/i in diameter), 

 and in colony from the Philippine Islands (45-60/^), but rather small 

 in the two Japanese colonies (23-26/* in diameter). Some crystalline 

 needles are embedded. Colony from Saipan Island has spicules which 

 seem to be in a somewhat degenerate state, being composed of a number 

 of thin needlelike rays projecting from the central spherical bodies. 

 In a perfectly preserved state, spicules are of moseleyi-iy^o, and consist 

 of rays short, or of moderate length, both bluntly tipped. Number 



