THE ACTINIANS OF PORTO RICO. 
359 
Genus CALLIACTIS Verrill. 
Calliactis, Verrill, 18C9, p. 481; Hertwig, 1882, p. 73; Haddon, 1898, p. 456; Carlgren, 1900, p. 55. 
Adamsia, McMurrich, 1893, p. 182. 
Metridinx with prominent cinclides, arranged in from one to several horizontal rows toward the 
base of the column; no verruca;. Column usually divided into scapus and capitulum; scapus secretes 
a membranous cuticle which is shed from time to time; very changeable in form, in full expansion 
elevated, subcyclindrical, with a broadly expanded base, in retraction forming a low, flattened cone 
or convex disk. Pedal disk with a tough cuticle. Tentacles numerous, slender, subulate, highly 
contractile. Acontia highly developed, emitted through the cinclides and oral aperture. 
The above definition is altered somewhat from Haddon’s, which was founded upon that of 
Verrill, so as to include the cutieular formation. Carlgren does not mention if C. polypus is possessed 
of a capitulum. 
Verrill (1869) erected the genus Calliactis with C. decorata (Drayton) as the type, and included the 
Actinia tricolor of Lesueur to be here described. He distinguishes it from the genus Adamsia of Forbes, 
which exhibits a peculiar low-spreading method of growth involving a union of the polypal base 
around the shells of mollusks. All the other characters agree so closely that it is very doubtful whether 
the mere peculiarity of growth should be considered sufficient to constitute a generic distinction. 
Hertwig in the Challenger Report (1882, p. 74) retained Verrill’s genus for C. polypus, but in the 
Supplement (1888, p. 3), following Andres, he states that it must be termed Adamsia polypus. Haddon 
(1898) in his latest paper retains the two genera, and Carlgren (1900) also admits Calliactis. McMurrich, 
however, employs Adamsia as the generic term for the present species. 
Calliactis tricolor (Lesueur). Pis. Ill, XII, Figs. 12, 45, 46. 
Actinia tricolor, Lesueur, 1817, p. 171. 
Adams&i tricolor, Milne-Ed wards, 1857, p. 281; Duchassaing et Michelotti, 1886, p. 134; McMurrich, 1898, p. 234, pi. i, figs. 6,7; 
pi. it, figs. 1,2. 
Calliactis tricolor, Verrill, 1869, p. 481. 
Actinia bicolor, Lesueur, 1817, p. 171. 
Calliactis bicolor, Verrill, 1869, p. 481. 
Adamsia egeletes, Duchassaing et Michelotti, 1866, p. 134, pi. vi, fig. 17. 
Calliactis egletes, Verrill, 1869, p. 481. 
Qereiis sol, Verrill, 1864, p. 214 ( Actinia sol, Agassiz, MS., 1849). 
Adamsia sol, McMurrich, 1893; p. 183. 
Fifteen specimens of an Adamsia, associated with fragments of an old Cassis shell, were obtained 
from Mayaguez Harbor. Polyps of very different sizes are represented, the basal diameter of some 
measuring only 1.2 cm., while others are 3.5 cm. They are rarely more than I cm. in height, complete 
retraction having taken place in every case. In all the base is very irregular in outline, the polyps 
having adapted themselves to the spiral convexities of the incrusted shell. Patches of a dark-brown 
cutieular membrane in some instances persist between the incrusted surface and the basal ectoderm. 
The upper part of the column is infolded to such a degree that the disk and tentacles are com- 
pletely hidden, only a small aperture remaining toward the middle of the flattened apex. The 
columnar surface is strongly ridged both vertically and transversely, being divided into small, square, 
or rhomboidal areas, which give a coarse tuberculated appearance to the polyps. For the most part 
the column is devoid of any cutieular investment, and toward the base the wall is so thin as to permit 
of the mesenteries being seen. In most specimens the cinclides can be made out as two or three 
more or less complete circular rows of darker spots, disposed a short distance above the base. 
The above are practically all the external characters which can be made out on the Porto Rican 
specimens in their present retracted bleached condition, and from these alone it would be practically 
impossible to establish their specific identity among an admixture of species of the genus Adamsia. 
But the specimens differ in no respect from similarly preserved Jamaican polyps whose identity as 
Adamsia tricolor is beyond dispute, being founded upon the living characters, while, as shown below, 
only one widely distributed species of Adamsia is known to occur in the West Indies. 
The species has never been fully described in its living condition. An account is therefore given 
below in some detail, as presented by the Jamaica representatives. McMurrich (1893, p. 234) has 
already partly described its anatomy. 
A damsia tricolor occurs plentifully in Kingston Harbor, attached totheshells of the living mollusks, 
Pyrula melongena and Fascioluria tulipa, on dead Pyrulci shells inhabited by the hermit crab, Petrochirus 
