42 UNITED STATES NATIONAL MUSEUM BULLETIN 251 



Figure 11. — Amaroucium crateriferum Sluiier: a, colony, 43 mm. X 40 mm. in extent; 

 b, schema showing outline of the 60 mm. X 40 mm. colony (concave depression on 

 underside is attachment surface to substratum). 



size. Anus bilobed, with thickened lips, opening at level of fifth or 

 sixth transverse vessel (numbered from the posterior end of the bran- 

 chial sac). Stomach situated near middle of abdomen, with 6 longi- 

 tudinal plications on its surface. Proximal portion of rectum dis- 

 tinctly constricted from midintestine, but no caecum formed there. 

 Testicular follicles numerous and arranged in two rows ( ? ) . 



Remarks. — Present specimens have a few more stigmatal rows and 

 also more stigmata in each row than the type specimens from the 

 Slhoga collection (18 rows and 11-16 stigmata in each row) and the 

 specimens from the Philippines (about 20 rows and 11-14 stigmata in 

 each row) . As figure la given by Sluiter evidently shows 21 stigmatal 

 roAA^s on the right side of the thorax, the numerical data in the original 

 description might possibly have been taken from smaller zooids. On 

 the other hand, there are considerably less longitudinal plications on 

 the stomach surface in the present specimens than in the type specimens 

 (12) and the Philippine specimens (about 10) , although this difference 

 cannot be regarded as a significant characteristic to separate the pres- 

 ent specimens from A. crateriferum. The number of tentacles is 

 small in the present specimens and in the Philippine specimens 

 ("ral her few") , though a considerably larger number in the type speci- 

 mens from the Sihoga collection (24) . 



