160 UNITED STATES NATIONAL MUSEUM BULLETIN 251 



end of stomach lying horizontally, nearly exposed behind branchial 

 sac and having 11 longitudinal plications, including typhlosolis. 

 Pyloric caecum very prominent. Anus situated at level of sixth to 

 seventh transverse vessel, plainly margined. Mantle and transverse 

 vessels of branchial sac pigmented purplish brown. Appearance of 

 second stigmatal row, which does not reach dorsomedian line, and 

 situation of anus seem to indicate the present small specimen assign- 

 able to a young colony of Botrylloides molaceus Oka. 



Remarks. — Botrylloides leachi (Savigny), Botrylloides chevalense 

 Herdman, and Botrylloides diegensis Ritter and Forsyth resemble 

 very closely Botrylloides molaceus Oka, and I am inclined to con- 

 sider that all of these four species might be treated under a single 

 species, B. leachi. However, until more crucial comparative studies 

 are made as to the appearance of the second stigmatal row and the 

 situation of the anus in these species, I wish to retain the name 

 B. molaceus for the form occurring in the western part of the 

 North Pacific. 



79. Botrylloides violaceus marginatus, new subspecies 



Figure 64 



HoLOTYPE. — USNM 11447: Palau Islands; east reef, about 1% mi. 

 south of Ngaremdiu, at end of reef called Uchulachei, east side of 

 Urukthapel; 7°13'05'' N., 134°26'30" E. (HO chart 6078, 1st ed.) ; 

 depth 0-20 ft., coral with patches of sand. GVF sta. 227, October 

 15, 1955. 



Paratype. — USNM 11455 : Palau Islands; outer reef at eastern end 

 of Urukthapel Island, about li/^ mi. north of Pkulasuch Point; 

 7°16'13'' N., 134°27'35" E. (HO chart 6076, 2nd ed.) ; depth 2-4 

 feet, in breakers; bottom covered with Turhinaria. GVF sta. 28, July 

 21, 1955. 



Description. — Two encrusting colonies from the Palau Islands are 

 described: one is very extensive and consists of three lobes respec- 

 tively 25 mm. X 20 mm., 25 mm. X 18 mm., and 20 mm. X 15 nmi. 

 in extent and 2 mm. in thickness, while the other colony is much 

 smaller and narrower, only 34 mm. X 8 mm. in extent. 



Test faintly milky white and transparent; a number of small, 

 elongated, purplish brown ampullae, w^hich appear roundish when 

 seen from surface, scattered in test. Systems elongated, largest in 

 present specimens consists of 73 zooids. Several roundish, common 

 cloacal apertures in each larger system. Zooids about 2 mm. in length, 

 situated nearly perpendicular or slightly inclined, reddish brown or 

 purplish brown. Coloration darkest at anterior side of thorax sur- 

 rounding branchial aperture, but fades on lateral side of body and 

 on atrial languet. Systems yellowish orange along axial parts, while 

 periphery heavily pigmented purplish or dark brown when animals 



