THE ACTINIAE'S OF PORTO RICO. 
351 
marina, and therefore might be capable of floating. Bunodeopsis antilliensis, with a similar habit, frees 
itself at times and floats with its basal disk upwards, and Duchassaing & Michelotti record the floating 
habit for C. eugenia. 
Anatomical examination revealed a small, though very definite circumscribed endodermal muscle, 
and therefore the form could not be regarded as a Cystiactis, as that genus is now understood from an 
investigation of C. tuberculosa Quoy & Gaimard. Though strong, the sphincter in this latter has been 
found by Professor Haddon and myself (1896) to be endodermal and diffuse, and the genus has been 
placed in the family Aliciidie. The possession of a circumscribed endodermal sphincter and of 
columnar evaginations marks the Porto Rican form as a member of the family Bunodactidx. 
Duchassaing & Michelotti give only the following description of C. eugenia: “Sp. parva, corpore 
tuberculis apice vesiculosis clavatis adoperto; tentaculis circiter 20 subaequalibus, translucidis, cylin- 
dricis, acutis, disco duplo et ultra longioribus ore conico exserto.” Their figure (pi. vr, fig. 1) shows 
the vesicles to be somewhat cylindrical and spirally disposed. In the end I have concluded that the 
safest course will be to regard the present species as distinct from C. eugenia. 
Viatrix globidifera is another long-looked-for West Indian species which has suggested itself, but 
it would undoubtedly be hazardous to compare this species possessing but a few spheroidal evaginations 
and tentacles with one in which the column is nearly covered with outgrowths and the tentacles are 
forty-eight in number. 
•In essential characters the new form differs very little from the genus Bunodosoma of Verrill, of 
which B. granulifera is the type, and may w r ell be included under it. Verrill (p. 44) defines the genus 
as follows: “General form and appearance as in Bunodadis, but the hollow verrucae, arranged in 
vertical rows, are rounded or subconical and do not form adhesive suckers. Upper or submarginal 
ones are larger in the mature specimens, more or less lobulated, but have nearly the same structure as 
those below, though they are described as perforated when living. Tentacles numerous; many mesen- 
teries, 12, 24, or«more pairs being perfect. Sphincter muscle well developed, endodermal, and circum- 
scribed.” The only difference between the characteristics here given and those presented by the 
species now under investigation is in connection with the marginal evaginations. In the Porto Rican 
species they are simple, while in Bunodosoma, as understood by Verrill, they become more or less 
lobulated. In the present state of our knowledge of this group, such a detail does not seem worthy of 
generic recognition, and I have therefore modified the definition of the genus to this extent. Perhaps 
the uniformity in size of the columnar evaginations in B. granulifera and the alternations of large and 
small rows in the new species may, as further representatives are added, call for generic distinction. 
External characters. — The base is flat and circular; preserved examples show radiating furrows, 
and the diameter is less than that of the column. In one specimen the base was adherent to a leaf of 
Thalassia marina. 
The column is erect, cylindrical, thin-walled, and covered for the most part with vertical rows 
of nearly globular vesicles, which increase in size from below upward. At the apex of the column 
they terminate in a cycle of larger conical outgrowths — the acrorhagi. Both specimens are deeply 
constricted a short distance above the base, hence there is some uncertainty as to the character of 
the verrucae in this region, but they appear to cease a little before the proximal termination of the 
column is reached. The vesicles are arranged in forty-eight rows, alternately large and small, a 
row corresponding with each mesenterial space, whether entocoele or exocoele. The twenty-four rows 
of smaller vesicles are opposite the twenty-four tentacles constituting the outermost cycle, while the 
rows of larger outgrowths, surmounted by the acrorhagi, alternate with the outermost tentacles. For 
the most part, the smaller vesicles alternate transversely with the larger, and all are so closely arranged 
that very little of the actual surface of the column remains exposed. The vesicles are simple, 
subspheroidal, sessile, hollow, and perfectly smooth, without any thickened areas which may represent 
special batteries of nematocysts. They are incapable of holding foreign particles to the column-wall. 
The acrorhagi are also simple and smooth, without any tubercular outgrowths or thickenings. A 
smooth, narrow fossa intervenes between the cycle of acrorhagi and the outermost cycle of tentacles. 
The tentacles in preserved specimens are smooth, short, broad below and narrowing above, 
entacmseous, and closely arranged. They are forty-eight in number, twenty-four constituting the 
outermost cycle; the cyclic arrangement is therefore, 6 6 12 24. 
The mouth is circular and widely open in the two specimens studied. The stomodteal walls are 
closely ridged and furrowed, and gonidial grooves are but weakly developed. 
2d— F. C, B. 1900— : 23 
