PACIFIC TUNICATA OF U.S. NATIONAL MUSEUM 53 



Three cup-shaped attachment processes arranged lineally, oval in out- 

 line on surface. Four pairs of ampullae present. In fully grown 

 larvae, dorsal end of ampulla vessel on each side extends posteriorly 

 almost to sensory organ, producing several small vesicles on the way ; 

 in addition, an isolated sliort vessel is at the posceroventral part of the 

 trunk, which produces four pairs of small vesicles (fig. 15e). Dorsal 

 brandies of the ampullae vessels and the isolated posteroventral vessel 

 not found in younger embroyos. Two pigment flecks of sensory organ 

 arranged anteroposteriorly. 



Remarks. — The structure of zooids in the present species resembles 

 closely that of F. tsutsuii The only clear difference between these 

 two species is in the appearance of systems which are stellate, quite 

 simple, and consisting of a small number (4 to 12, usually 6 to 8) of 

 zooids in P. tsutsuii^ but in P. vasculosum they are considerably com- 

 plicated, even in young and small colonies (see description of the 

 3 mm. long colony from Pearl Harbor, p. 51). How^ever, when the 

 specimens are not preserved perfectly enough to examine the appear- 

 ance of zooid systems, smaller colonies of these two species are con- 

 fused and exact identification is practically impossible. Polyclhium 

 7ieptunium Hartmeyer and P. inacwphyUum Michaelsen also resemble 

 the present species in having 12-13 stigmatal rows, but in those species 

 the systems are "Doppelreihen-netzsystemen." 



15. Polyclinum constellatum Savigny 



Figure 16 



Polyclinum constellatum Savigny, 1810, p. 189, pi. 4, fig. 2; pi. 18, fig. 1.— Van 

 Name, 1921, p. 299, figs. 1, 2.— Michaelsen, 1923, p. 8.— Van Name, 1930, p. 422, 

 fig. 3.— Van Name, 194.5, p. 68, fig. 28. 

 Polyclinum festiim Hartmeyer, 1905, p. 400, pi. 13, figs. 6-7.— Van Name, 1918, 

 p. 102, fig. 111. 



MATERIAL EXAMINED 

 Japan : Off Omai Zaki, Honshu ; Albatross sta. 3730. One colony, a roundish 

 mass 17 mm. X 11 mm. in extent and 9 mm. in height, of a soft, gelatinous con- 

 sistency and yellowish white, with a sparse coating of sand grains on the surface 

 (USNM 11630). 



Palau Islands : Eastern end of Urukthapel Is. ; GVF sta. 28. One specimen 

 13 mm. X 12 mm. in extent and .5.5 mm. in thickness ; entire surface densely 

 covered with coarse, white sand grains about 0.5 mm. in diameter (USNM 11456). 

 GiLBEKT Islands: Onotoa Atoll; A. H. Banner, sta. B^. Five colonies, the 

 larger ones from 33-35 mm. X about 20 mm. in extent, and 8-12 mm. in thickness ; 

 cushion-shaped and attached to colonies of zoanthids or attached to coral sand 

 grains beneath ; surface of colonies encrusted with sand grains to various degrees, 

 very heavily in some colonies (USNM 11518). 



Description. — Test soft, gelatinous, translucent or transparent, and 

 yellowish white to brownish. Surface coated with sand grains in 

 varying degrees but never impregnated with them, except for some 

 colonies in which sand grains and fecal pellets are embedded in the 



