276 bulletin: museum of comparative zoology. 



x\s Liitken gave no figures, Koehler's photogTaphs are very useful, 

 and his fig. 6 is particularly satisfactory as it shows the longitudinal 

 stripe on the arm, which is referred to in Liitken's description and is 

 well-marked in all my Tobagoan specimens. The absence of this 

 stripe in the smaller specimen figured by Koehler (fig. 4) is probably 

 due to the long sojourn in alcohol. The character of the marginal 

 papillae of the disk is well brought out in Koehler's fig. 4, 5. Koehler's 

 specimens were from off Cape Hatteras while Liitken's type was from 

 St. Thomas. At Tobago I found this species in the sandy mud on the 

 southeastern side of Sandy Point, Buccoo Bay, in company with 0. 

 lutkeni and several species of related genera. It was not common 

 but three entire specimens and the arm of a fourth were secured. 

 The smallest is 2.5 mm. across the disk and has arms 23 mm. long, 

 while the largest has the same measurements 9 and 90 mm. respec- 

 tively. In all the specimens the coloration was the striking feature 

 in life for while the disk was gray, the ground-color of the arms was 

 pale yellowish, more or less clouded or blotched with yellowish green 

 and the longitudinal stripe on the dorsal side of the arm was a dis- 

 tinctly deeper green. In the preserved specimens the green is fading 

 and becoming more or less dusky. All these individuals had a similar 

 but fainter stripe on the under side of the arm but this has now nearly 

 disappeared in the smallest specimen, though still obvious in the 

 others. 



Ophiophragmus chilensis. 



Ophiolepis chilensis Miiller and Troschel, 1843. Arch. f. naturg., 9, 1, 



p. 120. 



Amphiura chilensis Liitken, 1859. Add. ad hist. Oph., pt. 2, p. 122. 

 Amphiodia chilensis Verrill, 1899. Trans. Conn, acad., 10, p. 313. 



The discovery that this species belongs in Ophiophragmus was due 

 to the critical examination of the Amphiodias, in connection with 

 the description of a new species of that genus taken at Tobago. 

 There are in the M. C. Z. collection two brittle-stars from Chile, 

 which were labeled Amphiodia chilensis; one, the specimen collected 

 by the Hassler at Talcahuano, the other a somewhat larger specimen 

 collected by Plate at Calbuco and received, in exchange, from the 

 Berlin Museum. The latter has an imperfectly developed "fence" 

 of marginal papillae, just like that of 0. wurdemanii, but the papillae 

 are thicker and more capitate than in the Florida species. There is 

 no doubt that this Calbuco brittle-star is an Ophiophragmus, if the 



