Xarkativp: of Bahama Expedition. 215 



Among the cci^lenterates a great quantity of gorgonians 

 were secured, most of which have not vet been identitied. 

 Among them were Jir/arcinii (f<f)csf/iii()u PalL. a hea\'y. tiesh\" 

 species of a pink or purphsh color, and without a horny axis 

 cyHnder. Tliis is a good form to study, as the polyps are 

 large and will expand freely in aquaria. PlexaiircJla dicliotonia 

 is very common, with thick, flesln' l")ranches covered with slit- 

 like apertures, and luu'ing the calicles included, and a well 

 marked axis cvlinder. EiDiicca touriicforti M. Edw. has thick 

 branches and exserted calicles. The spicules of this gorgonian 

 are among the most beautiful of objects under the microscope, 

 being unusually large and brilliantly colored with pink and 

 red and purple. Eiiiiicca toiirucfurti M. Edw. is flabellate in 

 form, verv dark in color, and has non-retractile poh'ps. The 

 spicules are very large and massive, without coloration. The 

 most beautiful of the gorgonians is Rhipidig-orgia flabcUuui 

 .Linn., the familiar ••sea-fan." The red varietv sometimes 

 grows to a height of four feet, while the yellow specimens are 

 usually much smaller, seldom, if ever, attaining a height of 

 eighteen inches. Xiphigorgia aiiccps M. E. is also common, 

 with long branches resembling grass-like leaves of purple antl 

 yellow. The poh'ps are arranged in linear series. 



The reef corals at Spanish Wells were practically the same 

 as those found at the Tortugas, but several species were 

 more abundimt, notably Madrepora prolifcra Lam., of which 

 we secured a splendid series; Mxccdiuin fragile Dana was 

 found here and not at the Tortugas. IsophxUia dipsacca Ag. 

 is interesting from the fact that it has enormous nematocysts 

 and affords, when alive, an excellent opportunity to study these 

 remarkable organs. The nettling cells are found in the ten- 

 tacles wdiich surround the mouth of the polyp. It is hard to 

 determine just what kind of stimulus will cause the threads to 

 be projected. The writer has found that the tentacles mav 

 be touched with a needle or buffeted by the squirmings of a 

 small worm without effect. On the other hand, he has seen 

 scores of them set off without any known cause. A careful 

 study makes it evident that the threads are thrown out by 



