THE ACTINIANS OF PORTO RICO. 
365 
In the “Nachschrift” (p. 118) to his last paper Carlgren erects another new family, Homoslichan- 
thidce, for the species I have described as Homostichantlius anemone, but which he names II. duercleni. Its 
chief distinction from the family Stoichaciidte lies in the origin of many tentacles from each exocoele, as 
well as from the entocoeles, a character in which it agrees with the Aurelianidse. 
Genus STOICHACTIS Haddon. 
Stoichactidx ustfally of large size, column smooth below, with or without verruca: above. Ten- 
tacles short, simple, subulate, rounded or capitate, covering nearly the whole of the disc. A single 
tentacle from each exocoele constitutes the most peripheral cycle; usually many tentacles, arranged 
in a single radial row, arise from each entocoele. Sphincter muscle strong and circumscribed, or 
circumscribed-diffuse. Usually two gonidial grooves. 
Stoichactis helianthus (Ellis). PI. I, Figs, la, 16. 
Actinia helianthus , Ellis, 1767, p. 436, pi. xix, figs. 6, 7. 
1 mcosoma helianthus, Milne-Edwards, 1857, p. 256; Duchassaing et Michelotti, 1866, p. 122; Andres, 1883, p. 493. 
Discosoma anemone, McMurricb, 1889, p. 37, pi. i, fig. 8; pi. in, figs. 15, 16; pi. iv, fig. 1. 
Stoichactis helianthus, Duerden, 1900, p. 162, pi. xr, fig. 7; pi. xiv, fig. 1. 
This is a prominent Discosomid around Jamaica and other West Indian islands, including also the 
Bahamas (McMurrich), and the same must be the case in Porto Rican waters, for in the collection it 
is represented from most localities, often by numerous large specimens. It is met with on the coral 
reefs and sandy sea-floor at depths of two or more fathoms, and when alive different polyps vary much 
in color. Sometimes a number occur together in close contiguity, forming extensive patches. The 
variety of form which the polyps may assume on preservation is well illustrated by the many Porto 
Rican examples available for comparison. The tentacles especially differ in their appearance in the 
preserved examples, and, being very numerous,, determine the general appearance of the polyps. 
Sometimes they are shrunk and widely apart; at other times they are more distended, and clothe the 
disk more completely. Two somewhat extreme cases, obtained from Fajardo, are represented by the 
photographic reproductions on pi. i. The essential characters of the species have already been 
described by McMurrich (1889) and myself (1900). 
External characters. — The base is flat, usually adherent to the surface of rocks, and is a little 
larger in diameter than the lower part of the column. Preserved examples show strong, concentric 
and radiating ridges and furrows. 
The column is short and salver-shaped, narrowing a little above the base, and then expanding 
enormously in a crateriform manner; usually the column is partly embedded in sand and the distal 
region overhangs. The walls are smooth, thin, slightly transparent, and grooved. Distal ly, vertical 
rows of flat, oval, green verruca: occur, but are incapable of holding foreign particles to the column. 
The apex of the column is rounded, devoid of acrorhagi, but with a very distinct fossa. The column is 
incapable of being infolded completely so as to cover the disk. 
The disk is flat and greatly expanded. By far the greater part is covered with radiating rows of 
tentacles, more crowded toward the periphery. In young polyps a cyclic order in the radial extent 
of the different rows of tentacles can be established, but is mostly lost in large specimens. A single 
outermost cycle of exocoelic tentacles alternates with all the radial rows; the latter are entocoelic. 
The tentacles are short and digitiform, but vary a little in shape and size, according to the degree of 
distension. In the preserved condition they may become vesicle-like, or remain conical or digitiform, 
the surface finely fluted from apex to base. Small tentacles are seen in process of growth around 
the margin, but within the exocoelic cycle. 
The central naked area of the disk is smooth, and the peristome is somewhat elevated. The 
•mouth is large and oval. Two gonidial grooves are usually present, readily distinguished by their 
thickened margins; rarely three may be present. 
The base is white or cream colored; the column white or cream below, and a little darker above. 
Large, irregular green patches may occur on the column, and distally vertical rows of small, oval, 
green areas represent the verruca:, their number and closeness varying much in different rows. The 
disk may be a light or dark olive brown, and the tentacles the same, but irregular patches of varying 
intensity are exhibited. The peristome is a brownish yellow, the lips a deep rich yellow, and the 
stomodseal wall white. Color varieties are frequently met with. In one the column and disk are 
almost entirely colorless, and the tentacles a clear sulphur yellow. 
