332 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
About a dozen different colonies belonging to the genus Zoclrilhus are contained in the Porto 
Rican collection. Externally they are divisible into two well-marked groups: (1) Colonies possessed 
of a continuous incrusting eoenosarc, from which small polyps rise as mammiform or cylindrical 
upgrowths, and are practically of the same diameter throughout. (2) Colonies without a continuous 
incrusting ccenosarc, the polyps forming irregular clusters, connected with one another and with for- 
eign debris by narrow stolons, flattened coenosarcal expansions, or growing directly from one another. 
In these the individual polyps are mostly club-shaped and pedunculated, but they may be cylindrical. 
The representatives of the genus Zoanthus are very variable in form, dimensions, number of 
tentacles, and color, according to the conditions under which they are living, so that where an abun- 
dance of material is available it becomes very difficult to secure constant and specific characters, and 
thus to identify the different types with the descriptions of other workers. 
Verrill in a recent paper (1900) recognizes ten West Indian species, including those from the 
Bahamas and Bermudas. Already many synonymic difficulties have been introduced. In my 
account of the Jamaican Actiniaria I have placed the colonies with a continuous incrusting eoenosarc 
under Duchassaing & Michelotti’s term, Mammillifera pulchellus, a form which these authors believed 
to be but a variety of the M. nympheie of Lesueur. Externally they exhibit no differences from the 
Bahaman specimens which McMurrich has determined as M. nympliex, but the sphincter muscle of the 
two apparently differs to such a degree as to warrant their separation as distinct species. Trans- 
verse and longitudinal sections of the Porto Rican specimens of the Mammillifera type exhibit all the 
characteristics of the Jamaican specimens, and I have therefore determined them as Zoanthus pulchellus. 
Verrill (1900, p. 566) in a footnote points out that Lesueur (1817, p. 178) was evidently in error in 
stating that the tentacles in M. auricula are 26 to 30; Lesueur’s transverse section of the same species 
represents 61 mesenteries, and as the number of tentacles corresponds with the number of mesenteries 
it may be assumed that the former are about 52 to 60. As McMurrich distinguished his M. nympheie 
from M. auricula mainly on the tentacular differences it is clear that the determinations of McMurrich 
and myself become very difficult of comparison with the original types of Z. auricula, Z. nympliex, and 
Z. pulchellus, especially considering that the external characters upon which alone the three are 
founded are so very variable. I do not at present see that any advantage is to be gained by attempting 
to modify the synonymy already adopted, and therefore retain Z. pulchellus for the forms above 
mentioned. The characters as exhibited by the Jamaican and Porto Rican representatives seem 
clearly enough defined to enable them to be recognized at any time. 
The Jamaica colonies with mostly clavate, pedunculated polyps, irregularly united by stolons, 
etc., I previously identified as the Z. flos-marinus of Duchassaing & Michelotti, mainly from the 
description which McMurrich gave of Bermudan specimens identified by him as this species. Verrill, 
however, has placed the Z. flos-marinus of McMurrich under his new species, Z. proteus, and the 
Jamaican Z. flos-marinus as a doubtful synonym of Z. socialus. Judging from the figure of the sphincter 
of Z. socialus which McMurrich (1898) has recently given I am inclined to think that Verrill’s suggestion 
is the best solution of the present difficulty. There is nothing in Lesueur’s description of Z. socialus, 
nor in the more detailed study given by McMurrich, which does not occur in the specimens I have 
had under examination. I have therefore in the present paper placed the Jamaican Z. flos-marinus as 
a synonym of Z. socialus, and identify the Porto Rican specimens as this species. The form possessing 
about 36 tentacles, which Duchassaing & Michelotti describe as Z. flos-marinus, has therefore yet to be 
rediscovered. 
It is regrettable that Verrill has not given a figure of the sphincter muscle of his new species, 
Z. proteus; for among the external characters which he gives there are none which may not occur in 
the species already recognized. To my mind the validity of the new species can only be established 
by showing that the sphincter possesses a characteristic form, or that some other constant anatomical 
feature occurs. 
Zoanthus pulchellus (Duchassaing & Michelotti). Pis. II, IV, Figs. 2, 3, 14. 
Mamillifera pulclicUa, Duchassaing et Michelotti, 1866, p. 137, pi. vi, fig. 4 (an varietas M. nymphxxf). 
Zoanthus puclieUus, Duerden, 1898, p. 341, pi. vim, fig. 3; pi. xvma, figs. 3, 4. 
External characters. — The polyps are erect, cylindrical, short or elongated, thin-walled, smooth, 
usually closely arranged, and rise from a thin, tough, incrusting ccenenchyme. Where widely sepa- 
rated they generally appear on retraction as low mammiform prominences. On retraction they may 
