POLYPS AND CORALS. . 71 



.25 of an inch across the disk, are relatively higher, but 

 the disk considerably exceeds the column. The tubercles 

 are much fewer and relatively larger and plainly arranged 

 in single radiating series. 



The figure, though drawn from life, represents the base 

 as altogether too narrow and the tubercles not sufficiently 

 numerous. 



Color variable, usually purple, often light green. 



Port Lloyd, Bonin Islands, attached to branches of 

 Madre])ora, in one fathom. Dr. Wm. Stimpson. 



This species resembles Ricordea florida D. and M., but 

 the latter becomes compound, having^several mouths when 

 adult. 



HoMACTis Verrill, gen. nov. 



Column low, cylindrical, with a distinct fold near the 

 margin, substance firm, surface smoothish. Disk not 

 much wider than the column, concave, the whole surface, 

 except a narrow region about the mouth, covered with 

 small, rounded, perforated tubercles, arranged in wide 

 radiating series, in which they are crowded in several 

 transverse rows. Tentacles marginal, in life longer, with 

 imperforate tips ; in alcohol scarcely different from the 

 tubercles in appearance. Mouth large. 



HoMACTis RUPicoLA Verrill, sp. nov. 



In alcohol the base is equal in width to the column, 

 which is low, cylindrical, with many strongly marked 

 transverse folds due to contraction, which are crossed by 

 fine longitudinal wrinkles. Just below the tentacles is a 

 well marked fold ; substance firm. Disk broad, but 

 scarcely exceeding the column, deeply concave, covered 

 by about fifty broad, radiating groups of very small and 

 numerous, rounded, perforated tubercles, which are closely 

 crowded and form four or five irregular transverse rows 

 in each radiating band. These radiating groups corre- 

 spond with the internal chambers, and the principal ones 

 extend from near the mouth to the circumference. Be- 

 tween these are smaller ones, some of which extend half 



