J. E. Duerpen—Jamaican Actiniaria: Part I—Zoanthee. 363 
mesenteries on each side, but in one polyp there are ten on one side and nine on 
the other; in another seven and nine, arranged as shown in fig. 8. The funda- 
mental distinction of the Zoanthide into Brachyenemine and Macrocneminz is 
departed from in the sections of two polyps represented. In fig. 2 it is seen that 
the normal brachyenemic arrangement holds on the left side, while the macrocnemic 
is present on the right side. This is also the case in fig. 3, only the order is 
reversed. 
The manner of the connexion of the mesenteries to the cesophagus is best 
shown in fig. 2, Beyond the sulear directives there is a considerable interspace 
before the other mesenteries are reached, and then the interspaces are about equal. 
The mesenteries are very thin near their attachment to the column-wall, but 
enlarge a little to form the basal canal. The imperfect mesenteries do not 
project far. The endoderm contains zooxanthelle and pigment matter, and the 
mesoglea is extremely thin. The parieto-basilar muscles are well developed. The 
basal canal is usually rounded, and contains numerous large oval nematocysts. 
The reflected ectoderm and mesenterial filaments present the usual structure. 
The digestive endoderm is very thick and granular. 
Gonads.—No gonads were present in numerous examples sectionized. 
Caenenchyme.—The basal portion of the ccenenchyme is very crowded with 
canals in communication with the basal canals in the mesenteries and containing 
pigment granules and large oval nematocysts. Ccelenteric canals connect one 
polyp with another. 
This species, first described by Ellis and Solander, is one of the two original 
representatives of the genus Polythoa of Lamouroux. The material upon which it 
was founded was originally obtained by Sir Hans Sloane from Jamaican waters, 
probably about the year 1687, when Sloane visited the island. The specimens 
were deposited by him in the British Museum; the collections of the famous 
naturalist and physician forming the nuclei of that national institution. Sloane, 
however, in his “ Voyage,” which deals largely with the Natural History of 
Jamaica, has no description of the objects beyond that given on the plate con- 
taining his three figures, ‘‘ Lapidis astroitidis sive stellaris primordia,” implying that 
this, along with the Alcyonium ocellatum, of Ellis and Solander, are the beginnings 
of the stony star-like corals, so abundant in the seas around. 
Ellis and Solander first named, described, and again figured Sloane’s specimen. 
Although their description, ‘‘ This whitish leather-like Aleyonium is spread over 
rocks, with many convex teat-like figures, hollow in the middle, with a faint star- 
like appearance, and united close together,” is rather incomplete for purposes of 
identification, still the excellent figure they give of a colony leaves me little 
hesitation in considering the form described above as the same these two authors 
812 
