66 MCMURRICH. [VoL. III. 
lar cavities, apparently without any muscle fibres and with a 
darkly staining border. 
The tentacles are rather short and somewhat acuminate, and 
are arranged in two cycles, there being from 31 to 34 in each 
cycle. The disc has its mesogloea densely loaded with enclosed 
cavities, containing cells probably ectodermal and muscular in 
their nature (Pl. IV., Fig. 21). The stomodzum (PI. IV., Fig. 
20) is peculiar in being rounded at its dorsal edge, but abruptly 
truncated at the ventral or gonidial edge, the directives being 
attached one to each angle formed by the truncation. 
The mesenteries are arranged on the microtypus and are very 
slender, the musculature being only slightly developed and ar- 
ranged as in Zoanthus sociatus. The basal canal in many cases 
forms a circular cavity similar to those forming the greater por- 
tion of the sphincter, but in the majority of cases is slender and 
produces only a slight enlargement of the base of the mesen- 
tery. None of the specimens examined possessed reproductive 
organs. 
Genus CoRTICIFERA (Les.), Erdmann. 
Synon. — Palythoa auct. 
Zoanthidz, with sand or foreign matter imbedded in the 
mesogloea, and the polyps imbedded throughout their greater 
extent in ccenenchyma ; sphincter muscle single enclosed in the 
mesoglcea ; mesenteries arranged on the microtypus. 
This term was first proposed by Lesueur (’17) for the recep- 
tion of the Zoanthidz, in which the polyps were imbedded 
nearly to the tentacles in a coenenchyma. Later the term 
Palythoa was limited so as to include forms with this character- 
istic (Verill 68 and Gray ’67), and Lesueur’s term passed out of 
use, but has been revived again by Erdmann (’85). 
14. Corticifera flava, Les. 
Synon. — Corticifera flava — Lesueur, 1817. 
Palythoa (Corticifera) flava — Duchassaing and Michelotti, 1860. 
Palythoa mammillosa, var. flava — Duchassaing and Michelotti, 1866. 
This form was very abundant at New Providence, forming 
colonies of from 15—22.5 cm. in length by from 7.5-12.5 cm. in 
breadth in the shallow water along the shores. I identify it 
