342 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
In its transverse outline the stomodaeum varies in different regions and in different polyps. In 
most examples it is pyriform, truncated toward the groove, and the ectoderm forms seven or eight 
vertical folds on each side, the gonidial groove occupying nearly one-third of the diameter. In other 
polyps the stomodaeum may he nearly circular and devoid of folds. The ectoderm is strongly ciliated 
and loaded' internally with yellow pigment granules. 
The mesenteries present the normal brachycnemic arrangement in most cases, but irregularities 
may occur, as where a polyp may be macroenemic on one side and brachycnemic on the other, while 
one polyp has bepn met with in which the former arrangement occurred on both sides. The number 
of pairs varies from about 14 to 17. The mesenterial mesoglcea is very narrow except toward the 
column-wall, where it enlarges and contains the basal canal and sinuses. These occupy almost the whole 
transverse width in the upper region of the mesenteries, but are more restricted below. The basal 
canals are well developed in both the perfect and imperfect mesenteries and, in addition to cells with 
granular protoplasm, contain many oval nematocysts and pigment particles; below they are connected 
with the sinuses in the coenenchyme. The endoderm on the lower part of the mesenteries is enormously 
thickened and loaded with nutrient granules. 
The reflected ectoderm and mesenterial filaments are of the typical Zoanthean character. 
Spermaria occurred on the complete mesenteries of some of the polyps examined. 
Localities. — St. Thomas (Dueh assa ing & Michelotti), Jamaica (Duerden), Cuba (U. S. Fish 
Commission ) . 
ACTINIARIA (restr.). 
Actinozoa in which six pairs of primary mesenteries ( protocnemes) arise bilaterally, and usually 
all become complete. The two axial pairs constitute the directives, in which the retractor muscles 
are on the faces turned away from one another; the remaining four constitute unilateral pairs, two on 
each side of the polyp, in which the retractor muscles are on the faces turned toward each other. 
Additional mesenteries (metacnemes) arise as unilateral pairs within the six primary exocoeles, 
either simultaneously or successively in a bilateral manner from one aspect of the polyp to the other, 
and usually constitute one or more alternating hexameral cycles beyond the primary; sometimes the 
hexameral plan is departed from. One or more tentacles may arise from each mesenterial chamber. 
The column-wall occasionally possesses an ectodermal muscle and ganglion layer. Two gonidial 
grooves usually occur. Parieto-basilar and basilar muscles are generally developed, and usually ciliated 
bands on trilobed mesenterial filaments. The polyps are solitary, never forming colonies, and no 
incrusting or continuous skeleton is produced. 
Order ACTININ# Milne-Edwards. 
Actiniaria in which the tentacles are simple, and arranged in alternating cycles at the periphery 
of the disk. Only one tentacle communicates with each mesenterial chamber. 
The orders Actininx and Slichodactylime are here employed with their older significance, not in 
the manner adopted by Carlgren (1900a). 
Family PHYLLACTID/E Andres. 
Actiniaria with a smooth or partly verrucose column; tentacles simple, subulate, situated at 
some distance from the apparent discal margin; between the tentacles and margin are 1 >w tentacular 
structures or foliose areas. Sphincter muscle endodermal, more or less circumscribed, lying in the 
interval between the tentacles and the frondose or tentacular structures. Two or more orders of 
mesenteries perfect. 
The family Phyllaclidx has been studied anatomically mainly by Professor McMurrieh (1889, 1893) . 
It embraces at least the following genera: Phyllactis M. Edw., Oulactis M. Edw., Diplactis McMur., 
Crcidactis McMur., and Asteractis Verr. Haddon (1898, p. 437) includes the genus Hoploplioria of H. V. 
Wilson (1890), but I have shown (1899) that Wilson’s species, II. coralligens, is a Lehr uni a and must- 
therefore be placed with this genus under the family Dendromelidtv. The West Indian Hoploplioria 
never exhibits anything corresponding with the extensile and variable capitulum which Haddon 
describes for his //. cincta. 
