98 UNITED STATES NATIONAL MUSEUM BULLETIN 251 



whitish, faintly yellowish orange, pale brownish, grayish brown or 

 greenish. Such coloration is due partly to zoochlorellae contained in 

 the lacunae system and partly to the amount of pigment deposited in 

 the surface layer of the zooidal stratum. Spicules found most densely 

 at the periphery and the bottom layer of the colony, consequently the 

 margin and underside of colonies are usually whitish. Spicules de- 

 crease, however, in varying degrees in the central portion on the 

 surface of the colony, especially markedly above respective zooids. 

 There the greenish or brownish (USNM 11678 from the Philippines) 

 tint of zoochlorellae is seen through the translucent test. Spicules 

 distributed nearly evenly in some of the Palau specimens, in others 

 rather dense in the surface layer of the zooidal stratum, but quite 

 sparse between zooids. The size of spicules varies considerably, 

 always smaller than in LisHocIinum patella; 20-25/x in diameter in 

 some colonies, but 30-45/i in others. Generally of the candidum-type, 

 but larger ones often of the patella-type, and worn on surface ; some- 

 times spicules consist of rather fewer rays (fig. 32/). In some Palau 

 specimens, small granules formed on surface of colony by aggregated 

 spicules, especially numerous at some places along the periphery; 

 there such granules elongated to small finger-shaped protuberances. 

 Superficial spiculeless layer distinct. Thoracic and hypoabdominal 

 lacunae well defined and contain a large amount of zoochlorellae, 

 ll-14:iM (Philippine specimens) to 18-21jti (specimens from the Gilbert 

 Islands), usually 15-1 8/x in diameter. One or two common cloacal 

 apertures in smaller colonies, up to four in larger ones. In some 

 specimens, aperture opens at end of a short siphon (fig. 32^) , in others 

 formation of siphon quite indistinct. Abdomen comparatively small, 

 approximately half as long as moderately contracted thorax. Bran- 

 chial aperture 6-lobed, thoracic organ situated near posteroventral 

 side of the wide atrial aperture at level of second transverse vessel on 

 each side of thorax, but may be missing in some dissected zooids. Six 

 to seven stigmata in each of four rows, wall of branchial sac between 

 stigmata pigmented brownish in some specimens. One testicular 

 follicle ; proximal part of vas deferens curves very slightly, never being 

 coiled. 



Remarks. — The pigmentation observed on some preserved speci- 

 mens seems to indicate that those colonies might be pale vermilion or 

 salmon pink when alive. 



41. Leptoclinum virens Harlineyer 



Figure 33 



Diplosoma viride Herdman, 1906, p. 341, pi. 8, figs. 34-40 ; pi. 9, fig. 6. 



not Let)tocUmwi virUlc Herdmau, 1906, p. 340, pi. 8, figs. 28-33. 

 Leptoclinum vircna ilarl lut^yer, 1909, p. 14r.(;.— Tokioka, 1942. p. .500, fig. 2; p). 4, 



figs. 1-3. 

 Diplosoma virens, Hastings, 1931, p. 102, fig. 16; pi. 3, figs. A, B. 



