﻿THE COASTS OF RHODE ISLAND AND NEW JERSEY. 139 



12. Astrangia astr^formis, M. Ed. et Haime, An. des Sc. Nat. 1849, 181 ; 

 Astrangia Dance, Agassiz, (non M. Ed. et Haime), Proc. Amer. Assoc. 1850, 69. 

 Poljpidom encrusting, flat or lobed, or pedicled and lobed. Polype cells short, ap- 

 proximate, fused together at their bases, cylindrical when free, subpolygonal when 

 crowded, external^ slightly costate. Calices infundibular. Columella slightly de- 

 veloped. Partitions up to thirty-five in number, slightly exserted, narrow, with their 

 margin oblique and serrated and their sides denticulated. Polypes cylindrical, pro- 

 jecting up to half an inch in length, translucent white, brown, red, or green ; tentacular 

 colorless, twenty-four in number, elongated conical, with rounded tips, situated in an 

 alternating circle ; mouth oval, situated at the summit of a conical proboscis. Coral 

 masses up to two inches in diameter. Point Judith. Found attached to rocks just 

 below low tide. , 



The polypidom of Astrangia astrceformis was first described by Milne Edwards and 

 Haime, in the Annales des Sciences Naturelles for 1849. The living coral was first 

 discovered by Agassiz who dredged it from a depth of nine fathoms off Gay Head in 

 Martha's Vineyard Sound.* At Point Judith I observed it in position attached to the 

 rocks a little distance below the lowest tide mark. It is especially interesting from 

 the fact that it is the only coral which has been discovered on the eastern shore of 

 the United States. Dead specimens have long been known, and the cabinet of our 

 Academy contains a number of them, among which is one attached to a fragment of 

 a Fulgur, from the coast of South Carolina. 



Finding the living A. astraformis afforded me an opportunity of examining its fili- 

 ferous capsules. These are especially abundant in the tentaculse, and in certain white 

 cords of the interior of the body. The function of the cords just mentioned is yet 

 unknown. I frequently observed them extruded from wounds of the body of A. 

 astrceformis. When detached they will spontaneously roll into a close coil ; and are 

 composed of filiferous capsules arranged in a radiant manner around a central cellular 

 axis, enveloped in a delicate, actively vibrating ciliated epithelium. 



The filiferous capsules of A. astrceformis are of two principal varieties. The first 

 variety consists of oval, or ovoidal cells, about .05 mm. long by .0155 mm. broad, 

 containing a spirally wound thread, as represented in figures 11, 12, plate X. The 

 second variety consists of smaller cells; those of the tentacular measuring about .045 

 mm. by .0067 mm., and those of the white cords .03 mm. by -0112 mm. ; and they 

 contain besides a spirally wound thread, a style extending from one pole to about the 

 centre of the cells, as represented in figures 9, 10. 



Both kinds of filiferous capsules, under certain circumstances not readily explained, 

 eject their contained threads with an astonishing degree of rapidity, and in so doing 

 the threads are absolutely turned inside out, as was first noticed by Agassiz,f and sub- 



*Proc. Am. Assoc. 1850, 69. -j- Proc. Am. Assoc. 1850. 



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