Boone, Echinodermata, Cruises of "Eagle" and "Ara," 1921-28 113 



The arms are wider and stouter than in 0. echinata. The under 

 arm-plates are small, slightly wider on the outer margin than long, 

 the outer margin rounded ; the side margins concave, the inner margin 

 narrow, straight. The side arm-plates bear four spines each; these 

 substantially increasing in size from ventral to dorsal of the series, 

 the dorsal spine being very stout, blunt-tipped. The upper arm-plate 

 is short and quite wide with the outer margin nearly parallel to the 

 inner one. 



References: Ophiocoma aethiops Lutken, Kongl. Danske Vidensk. 

 Selsk. Skrift. 5th Raekke, Bd. 5, p. 243, 1859.— H. L. Clark, 

 Bull. Amer. Mus. Nat. Hist., XXXII, p. 217, 1913; Mem. Mus. 

 Comp. Zool., XXV, p. 291, pi. 13, figs. 6, 7, 1915. 



Family: OPHIODERMATIDAE. 



Genus : OPHIODEBMA Muller and Troschel. 

 Ophioderma appressum (Say). 



Plates 66, 75B and 76B. 



Type: Say's type material came from the coasts of Florida and is 

 deposited in the Philadelphia Academy of Natural Sciences. 



Distribution: South Carolina at Charleston, Florida, Bahamas, 

 Bermuda, Jamaica, St. Thomas, Haiti, Venezuela, Brazil at Victoria. 

 Littoral to 50 fms. 



Material examined: Two specimens, taken at Porto Padre, Cuba, 

 2 fms., March, 1928, collected by the "Ara," Cat. no. 214. 



Color : Variable, one form is dark ash-gray ; another is dark green 

 marbled with yellow. 



Technical description: Disk diameter 19 mm.; arm length 115 

 mm. The entire abactinal surface is covered by regularly distributed, 

 coarse rounded granules which are also continuous on the outer lateral 

 and interbrachial spaces of the actinal surface. The genital slit is 

 long, granulated. Mouth papillae 16, or 18 to 20, unequal, but set 

 in an even row, the first slender, the second more than twice as broad 

 as the first, the third and fourth squarish; the fifth, sixth, seventh 

 and eighth slender, acuminate, slightly increasing in size in the order 

 named, the two teeth occurring at the apex of the jaw being substan- 

 tially larger than the rest. Teeth five, strong, blunt, triangular, in 

 series one above the other, the basal and uppermost ones of the series 

 being somewhat smaller and shorter than those between. Mouth- 

 shields heart-shaped, in some specimens with the height equal to or 



