﻿THE COASTS OF RHODE ISLAND AND NEW JERSEY. 137 



The principle trunks of the polypidom are nearly straight, and they give off alternat- 

 ing branches, provided with from one to half a dozen branchlets. The trunks are 

 black, and are annulated at their commencement, for a short distance after giving off 

 the branches, and at their termination. The branches have the same color and 

 character of annulation as the parent trunks. The branchlets are ochre-yellow, and 

 annulated at their commencement and termination, or occasionally throughout ; and 

 frequently they give off secondary branchlets. 



The polypes have the familiar form of the nine-pin, and are translucent white, 

 with two purplish red bands encircling the body at the base of the first two circles 

 of tentaculge. The stomach of the animal is pink, and is visible through the trans- 

 lucent parietes of the body, between the red bands. The head of the polypes is 

 conical, but in the expansion of the mouth is frequently observed to assume a cup 

 sliape. 



At the base of the polypes there is situated a radiating circle of twelve narrow, 

 cylindrical tentaculge, about one line in length, and capable of retraction, inflection, 

 or complete reflection. The neck of the polypes is surrounded by two circles, each 

 of six, comparatively short, cylindrical tentaculge, with large globular tips. 



The long tentaculge of Eucoryne elegans are composed of an axis of large, nucleated 

 cells, surrounded with a delicate muscular sheath, and enveloped in a thin, ciliated 

 epithelium. Beneath these tentaculge, extending their entire length, and enveloping 

 the tips, there is a stratum of nettling cells. The short tentaculge have the same 

 structure as the others, except that the nettling cells are accumulated entirely at their 

 ■extremities, and thus give to these their characteristic globular form. 



The nettling cells of Eucoryne vary in size, and present the same structure as the 

 principal ones of the fresh water Hydrge. When the cells are entire they appear as 

 oval capsules containing at their fundus a hemispherical mass of matter, which in 

 some instances has appeared to me to consist of a coiled thread, as represented in 

 figure 6, plate X. Above this mass or coil is a narrow oval capsule, within which is 

 a style, the point of which slightly projects from the summit of the nettling cell. 

 When the latter has emitted its thread, it appears partially collapsed, and from its 

 summit projects an irregular cone with four barb-like processes at the sides, and the 

 thread protruded from the apex, as represented in figures 5, 7. 



As in other compound polypes the soft structure of the animals is continued as an 

 axis throughout the polypidom. This axis contains numerous nettling cells, as large 

 and as well developed as those of the tentaculge. What can be their office in this 

 position ? 



Eucoryne elegans produces medusa-like buds, in numbers of one to four, situated 

 just above the position of the first circle of tentaculge. Very frequently a pair of these 

 buds become fully developed at the same time, and then appear larger than the parent. 



