Zoantharia — C utress and Pequegnat 
sions of the nematocysts of the two species but 
the distribution of the kinds is slightly different. 
Comparing E. leptoderma with E. gabrieli, 
we find that the colony and polyps of the 
former species are larger and the scapus and 
coenenchyme are thinner and more sparsely 
incrusted. Internally the marginal sphincter 
muscle of E. leptoderma, although slightly 
weaker, resembles that of E. gabrieli, but only 
in its upper part. Whereas the sphincter of 
E. leptoderma is short, that of E. gabrieli tapers 
gradually to a long tail which becomes alveolar 
(Fig. 7). 
One point of similarity that at first seemed 
important was the tendency of the cells of the 
mesogloea to be concentrated near the entoderm. 
Carlgren, 1951, stresses this feature as a char- 
acteristic of E. gabrieli. However, in the sections 
of a second polyp of E. gabrieli we found that 
these same cells are rather evenly distributed in 
the mesogloea. In the case of E. leptoderma, the 
concentration of cells of the mesogloea near the 
entoderm was rather obvious in all the polyps 
sectioned. 
When the mesenteries of the two species are 
compared in sections taken from a point half 
way between the end of the actinopharynx and 
the pedal disc, it is found that the microcnemes 
are about one half the length of the macro- 
cnemes in E. gabrieli while in E. leptoderma the 
free edges of the microcnemes scarcely extend 
beyond the margin of the column entoderm. In 
the former species, near the column, the meso- 
gloeal lamellae of both micro- and macrocnemes 
are greatly thickened, a feature which Carlgren, 
1951, does not mention. In contrast, the meso- 
gloeal lamellae of the mesenteries in E. lepto- 
derma are weak and there is little difference in 
their thickness from column to free edge (com- 
pare Figs. 6 and 8). The difference in appear- 
ance of this musculature in the two species is 
not due to differential contraction, for sections 
of both contracted and expanded polyps of 
E. leptoderma were compared with those of 
E. gabrieli. As the polyps of both species had 
inactive gonads, the different appearance of the 
mesenteries could not be due to differences in 
this physiological state. We think the differences 
between the mesenteries of E. leptoderma and 
E. gabrieli are morphological and constant. 
95 
Fig. 6. Transverse section of a macro- and micro- 
cneme of Epizoanthus leptoderma. Shown in the col- 
umn wall mesogloea are cells concentrated near the 
entoderm. Section taken from mid-column. Scale - 
.10 mm. 
It seems clear to us that, although E. lepto- 
derma possesses a few characters of both E. 
gabrieli and E. calif ornicum, for the most part 
these similarities are outweighed by the unique 
characters of each species, and in our estimation 
the three are distinct species. 
Epizoanthus induratum n. sp. 
Figs. 7-9 
TYPE MATERIAL: Holotype, U.S. Nat. Mus. 
Cat. No. 51054, one colony of about 60 polyps. 
From Corona del Mar, California, 1 mile S. E. of 
Newport Harbor entrance and one half mile 
