PACIFIC TUNICATA OF U.S. NATIONAL MUSEUM 51 



14. Polyclinuni vnsculosuni Pizon 



FlQUKE 15 



Polyclinum vasculosum Pizon, 1908, p. 223. 

 Polyclinum laxum Van Name, 1945, p. 71. 



MATERIAL EXAMINED 



Philippine Islands : Baliwasan ; W. R. Taylor, sta. 10. Two colonies meas- 

 uring 11 mm. X 8 mm. and 4.5 mm. X 3 mm. in extent, attached to eelgras.s 

 (USNM 11648). 



Marianas Islands : Saipan, entrance of Tanapag Lagoon ; P. E. Cloud, sta. 

 D-7. Nine colonies, the larger ones from 55 mm. X 20 mm. to 40 mm. X 25 mm. 

 in extent and 3.5 mm. to 6 mm. in thickness (USNM 11540). 



Haavaiian Islands: Oahu, Pearl Harbor; Paul Bart.^ch, collector, September 

 1920. Six: colonies, the larger ones roughly massive, IS mm. X 11 mm. to 

 15 mm. X 12 mm. in extent and 8-10 mm. in thickness ; attached to hydrozoan 

 colony (USNM 11755). — Oahu; T. II. Streets, collector. Three large colonies, 

 the largest measuring 145 mm. X 110 mm. in extent and 25 mm. in thickness 

 (USNM 11782). 



Description. — Colonies from the Hawaiian Islands are rather mas- 

 sive, attached to substratum by the underside ; tlie place of attachment 

 may be narrowed in some colonies and carries sand grains along its 

 margin. The upper surface of the colony is smooth and quite free 

 from foreign matter in some specimens, but it carries a small amount 

 of fine sand grains in others. The system of arrangement of zooids 

 consists of several radial canals converging in a common cloacal aper- 

 ture situated at the center of the system; many zooids are arranged 

 along both sides of these canals as shown in figure 15a. The largest 

 system examined liolds 137 zooids, while the smallest colony, about 3 

 mm. long, consists of a single system containing only 18 zooids. The 

 15-18 mm. X 11-12 mm. colonies contain about 6 systems on the sur- 

 face. These systems are defined distinctly by their yellowish coloration 

 attributable to the pigmentation on the upper side of thoraces and 

 atrial languets of zooids; the branchial apertures are surrounded by 

 markings of brownish pigment. The systems are 15 to 25 nnn. in 

 diameter on large colonies from Oahu Island. 



Colonies from Saipan Island are encru.sted and thinner than those 

 from the Hawaiian Islands; the surface is covered with fine sand 

 grains in various degrees. One of the colonies from tlic Philippine 

 Islands carries sand grains sparsely over the whole surface, while the 

 other holds sand grains only along tlie mtirgin of the colony, leaving 

 the area containing zooids quite exposed. There is a single common 

 cloacal apertuT'o on each colony and the zooids seem to be arranged in 

 a stellate system, although it is uncertain whether this system is a 

 typical stellate one as found in /'. tsKf.suii, or a complicated configu- 

 ration as seen in smaller colonies from the Hawaiian Islands, because 

 the condition of preservation is not perfect. C\)nnnon cloacal aper- 

 ture up to 1.5 mm. in diameter and bordered with many fine finger- 



