Part II. — Stichodactylince and Zoanthece. 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 mesoglcsal 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 stomodseal 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. 



I have identified this peculiar species as the Actinoporus 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 35 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 disc alone being exposed. Large specimens of Asteractis, which 

 have the same habit, occur in the vicinity. The skeleton of a crab, with all the 



