Part IT.—Stichodactyline and Zoanthee. 179 
upper region of the column, from which the figure was taken, the pennon is near the 
wall, but below it becomes further and further removed as the parieto-basilar 
muscle becomes stronger. 
The enormous circumscribed retractor muscle of each mesentery is arranged 
on branching, mesoglceal processes, the mesogloeal axis from which they 
arise being very thin. The muscle layer is continued along the face of the 
mesentery beyond the swelling as far as its connexion with the stomodeal wall, 
but the mesentery, as a whole, is very thin, both before and beyond the 
enlargement. The mesenterial endoderm contains abundant, deeply-staining, 
granular cells, and a nervous layer is distinctly separable in places, especially 
near the pennon. 
The mesenterial filaments are trilobed in the upper region, and exhibit the 
usual details of structure. The glandular and intermediate streaks are densely 
crowded with gland cells with brown granular contents. Proximally the middle 
lobe becomes highly glandular; and the mesenterial endoderm immediately behind is 
swollen. Its cells, along with those of the mesenterial epithelium, contain much 
dark granular matter. 
Female gonads occurred on prolongations of some of the mesenteries, but, 
owing to the crowded condition of the cavity it was impossible to determine their 
precise arrangement. In the gonad region the mesoglcea of the mesenteries 
becomes extremely thin, the endodermal epithelium is much broadened, and 
the contents of the cells highly granular in character, while pigment granules and 
granular gland cells occur along the margin. 
So far as could be determined from dissections, the twelve pairs of mesen- 
teries constituting the first and second orders, and including the directives, are 
fertile. 
[have identified this peculiar species as the Actimoporus elegans, of Duchassaing, 
although certain differences call for notice. The colour in the Guadaloupe speci- 
mens is stated to be blue, and the tentacles reddish white, while the length is 
given as 83d mm. It is a species which suggests the possibility of much colour 
variation, but it seems a little remarkable that the Jamaican specimen should 
be three or four times larger than the others. 
Only a single specimen was obtained from along the shore to the east of Wood 
Island, Port Antonio, during the temporary establishment at the latter place of a 
Marine Laboratory in connection with the Johns Hopkins University. This was 
collected by Dr. H. L. Clark, and kindly handed over to me. Although the 
locality was afterwards carefully searched on many occasions, no other example 
could be found. The column was buried for a considerable distance in the 
muddy sand, the dise alone being exposed. Large specimens of Asteractis, which 
have the same habit, occur in the vicinity. The skeleton of a crab, with all the 
