REPORT ON THE CRINOIDEA. 305 



Other Localities.— S.S. "Dacia," 1883; lat. 34° 57' N., Long. 11° 57' W.; 533 

 fathoms. 



The "Talisman," off Rochefort ; 1500 metres. 



The Caribbean Sea ; abundant from 73 to 278 fathoms. 



Remarks. — This singular species will be fully described and it3 variations illustrated 

 in the Report on the Comatulse of the " Blake " dredgings. It was first obtained by the 

 "Porcupine" in 1870, though I never saw the type till 1883, nearly five years after 

 it had been described by Pourtales from the dredgings of the " Hassler " expedition 

 at Barbados in 1872; and the Challenger had taken it at St. Paul's Rocks in the 

 following year. The " Hassler" specimens were described by Pourtales under the specific 

 name alata ; but at the same time he described an apparently different form from an 

 unknown Caribbean locality as Antedon pulchella ; l and when I subsequently found 

 reason, after examining the rich material obtained by the "Blake" in 1878-79, to unite 

 the two forms under one specific name, 2 pulchella seemed more appropriate than alata. 

 I therefore described the type as Actinometra pulchella. It has been found at over 

 thirty localities in the Caribbean Sea, ranging from 73 to 278, and possibly to 380, 

 fathoms ; while it presents a very singular instance of dimorphic specific characters. 

 Some individuals have ten arms, each with a syzygy in the third brachial ; but others 

 have twenty, with two articulated distichals and the first two brachials united by syzygy. 

 The " Blake " material contains numerous intermediate conditions between these two 

 extremes, e.g., individuals with twelve or fifteen arms, owing to the distichal series only 

 occurring on some of the rays. The Challenger specimen from St. Paul's Rocks has 

 twenty arms, with its full complement of ten distichal series. In the figured " Porcupine " 

 example, however, there are but nine distichal axillaries ; so that the number of arms 

 would only be nineteen, but for the presence of a single palmar axillary, which brings 

 the total up to twenty (PI. LII. fig. 1). 



This species is often an extremely difficult one to make out, owing to the obscurity 

 of the syzygial union between the first two brachials, as long as the arms remain whole ; 

 but when they drop away and the syzygial faces are exposed there can be no mistake 

 about the characters of the type. In some cases they have broken at the syzygy in the 

 third brachial ; though this is not always a syzygial joint, except perhaps in the two 

 outer arms of the ray. 



The Challenger's discovery of this species at St. Paul's Rocks extended its geographical 

 range very considerably, and lias probably also brought its bathynietrical range up to less 

 than 70 fathoms, the specimen having been obtained at some depth between 10 and 80 

 fathoms. In like manner the presence of this species among the " Porcupine " collection, 

 from 374 and 477 fathoms near the entrance to the Straits of Gibraltar, brings it into the 



1 Bull. Mus. Comp. Zo'61., 1878, vol. v. No. 9, pp. 215, 216. -Ibid., 1881, vol. ix. No. 4, p. 10. 



(ZOOL. CHALL. EXP. — PART LX. 1888.) Ooo 39 



