﻿460 ON CRYSTALLOMIA POLYGON ATA. 



The tentacles (see Fig. A) are short, and not at any time exsert beyond the body ; their 

 leno-th is about one sixth of an inch, and their general appearance much as in the 

 Actiniae. From the red clusters a few slender nettliiig-filameuts were usually ex- 

 tended ; the animal kept dropping them slowly and retracting them wholly or partially 

 by sudden starts. When most protruded, they were twice the length of the body. 

 The filaments themselves are colorless, or nearly so ; but the bulbs they bear at inter- 

 vals are red (Fig. D), and these give the red color to the retracted filaments. 



The filaments appeared to be tubular (Fig. D), and this tube extended into the bulbs, 

 through the slender pedicel by which they were suspended. The bulb contains a red 

 convoluted cord, — there being usually about six turns. The upper three of the turns 

 had an oblique striated appearance, arising from an oblique series of spiculse (Fig. D, a, 

 and Fig. F) ; but this oblique striation stopped short of the lower side of the turn ; 

 and, in the three lower turns, no such striation was seen in any part on the side of the 

 cord exposed to view. The surface of the red cord is very minutely hexagonal. The 

 spicule (Fig. F) were slender cells, glassy in aspect when separated from the cord ; 

 each contains a delicate and seemingly beaded thread, in several longitudinal convolu- 

 tions. They evidently correspond in structure^to tlie so-called " lasso-cells'" of Agassiz. 



The bulb bears below two tentacle-like cords (Fig. B, h, b'), as large in diameter as the 

 convoluted cord, being apparently the continuation of this cord, and indicating that 

 the convolution was probably in two coils. There is also along side an oMong pellucid 

 sac (Fig. D, c). The tentacle-like prolongations were very retractile. They were 

 covered •with papillae or minute prominences, and had a red color, nearly to the ex- 

 tremity ; the extremity was colorless, and showed a tube-like appearance within, as if 

 it were the termination of the tube of the filament above. The pellucid sac (c) is 

 about as long as the bulb. 



From near the mouth a canal, apparently alimentary (see Fig. A), passes in a straight 

 line along the middle of the body posteriorly, nearly to its posterior extremity, where 

 it terminates in an ovoidal organ of a deep brown color, a little glassy in aspect, or at 

 least shining. 



The Stephanomia hitherto figured and described have generally been mere frag- 

 ments of perfect individuals. These figures represent the glassy body at the posterior 

 extremity as wholly uncovered, and the nettling-filaments as centrally terminal at the 

 other extremity; and this would be the condition if the blocks of the posterior ex- 

 tremity and all of the ovoidal anterior portion had been lost. These blocks actually 

 drop apart very easily, so that this is no improbable supposition. 



I suggest for the genus the name Crt/stallomia, and for the species, C. jwlj/r/onata. 



