PART 5 A MONOGRAPH OF THE EXISTING CRIXOIDS 571 



Cape St. Vincent, Spain ; and the Princesse- Alice found it in great numbers on the Gor- 

 ringe Bank in 90 and also in 175 meters, and on the Seine Bank in 240 meters. 



Apparently this species usually occurs on a soft bottom of mud, or sand or gravel 

 with mud, as otherwise it would not have been so frequently recorded as abundant. 

 There are, however, only three bottom records, one of gravel and mud, one of gravel 

 and broken shells, and one of hard bottom. 



Prof. Jeffreys wrote (1866) that he had seen a number of this species clinging to 

 the rope several feet from the dredge when it was taken up from about 110 meters, no 

 part of the rope having lain upon the sea floor. Dr. F. A. Bather (1895) suggested that 

 these individuals had been swimming free and had fastened on to the rope as it passed. 

 But it is most likely that Jeffreys was mistaken in assuming that no part of the rope 

 lay on the bottom, as I do not see how it is possible to keep the line in front of the net 

 entirely clear of the ground. 



Prof. Koehler (1909) states that this species has been recorded by P. H. Carpen- 

 ter from Brazil, from a fragment of cable brought up from between 500 and 700 fathoms 

 (915 and 1280 meters). He refers to the specimens recorded by Carpenter (1891) from 

 near Madeira in 914 to 1279 meters which were found attached to the Brazilian cable. 

 The same error has been made by others. So far as known this species is wholly con- 

 fined to the eastern Atlantic. 



Gislen (1947) explains the occurrence of celtica near Tangier (that is close to the 

 threshold of the Mediterranean) by the hydrographic conditions hi that area. There 

 is a surface current about 100 meters deep passing into the Mediterranean, which has a 

 salinity of about 35 to 36% . Below this is an outgoing current with a salinity of 36.5 

 to 37foo, which follows the slope of the bottom downwards from the threshold at Gi- 

 braltar of 320 meters. He concluded that celtica was living in the mixed water between 

 the two layers. 



Within the last few years a number of specimens of celtica have been taken off 

 Sierra Leone by Dr. A. R. Longhurst while working at the West African Fisheries Re- 

 search Institute. These afford a considerable extension of the range to the southward. 



Occurrence of the pentacrinoids. The only known pentacrinoid of this species was 

 dredged by the Porcupine in 1870, off Cape Mondego hi 402 meters. 



History. This species was first noticed by Mr. Lucas Barrett, who described it in 

 1857 under the name of Comatula woodwardii from specimens he had dredged in the 

 Sound of Skye. Unfortunately Prof. Edward Forbes in 1852 had described a small 

 fossil from the Crag under the same name, so in 1858 this species was rechristened Coma- 

 tula celtica by Messrs. R. McAndrew and Barrett. 



The Rev. A. M. Norman's account of it in his monograph of the British echi- 

 noderms (1865) was taken from Barrett. 



For over twenty years the real relationships of the species were quite misunder- 

 stood. Wyville Thomson (1872, 1873) and, following him, P. H. Carpenter (1877), 

 Sladen (1877, 1878), and Nansen (18S5) applied the name celtica to the species now 

 known as Poliometra prolixa (see p. 590). The name was also used by Wyville Thomson 

 (1872, 1873), P. H. Carpenter (1877), Sladen (1877), Stuxberg (1886) and von Maren- 

 zeller (1878) for small specimens of Heliometra glacialis. 



In 1881 P. H. Carpenter was able to clear up the confusion regarding the name 

 celtica. One of Barrett's original specimens had been discovered by Prof. F. Jeffrey 



556-62207 38 



