ON NORTH AMERICAN ALCYOXARIA. 541 



PAPERS. 



37. Some Alcyonaria and a Stylaster from the West Coast 

 o£ North America. By Sydney J. Hickson, M.A,, 

 D.Sc, F.R.S., F.Z.S., The University of Manchester. 



[Received July 14, 1915 ; Read October 26, 1915.] 

 (Plate I.* and Text-figures 1-5.) 



Index. 



Morphology : Page 



Note on the Gonophoves of the Stylasteridai 545 



Geographical Distribution 541 



Systematic : 



Stylaster norvegicus Gumi 544 



Clavularia moresbii, s]). li 546 



Paragorgia arborea JAwn 548 



Primnoa luilleyi, sp. ii 551 



Caligorgia fraseri, sp. i\ 553 



Fsam7n.ogorgia teres V evr 554 



Although tlaere liave been several contributions to our know- 

 ledge of the marine fauna of the nortli-west coast of the 

 American continent in recent years, the Alcyonaria are almost 

 unknown, A long while ago specimens of a very large and 

 remarkable Sea-pen (Osteocella septentrional is), from the British 

 Columbian fishing-grounds, were examined and described, but 

 apart from this solitary example there is no record in the 

 literature of Zoology, so far as I have been able to discover, of 

 any other species of the Alcyonaria from this region. 



The division of sea-areas into zoo-geographical regions is always 

 a matter of great difficulty and controversy, and particularly so 

 along an uninterrupted coast-line extending from the Arctic 

 Circle to the Equator. Nevertheless, the study of the marine 

 fauna of the western coast of the Noi"th American continent 

 shows such changes in character as we pass from north to south, 

 as to justify an attem^pt to name and define regions of dis- 

 tribution. 



Sucli an attempt will not be made in this paper, but there is 

 jiist one point bearing upon this division into regions upon 

 which the study of this very small collection of Alcyonarians may 

 throw some light. 



In his papers on the MoUusca of the west coast of N. America, 

 Dall (1898) has given the name Oregonian region to the shoi-e- 

 waters extending from Point Conception, near the south boundary 

 of Upper California, to, and inchiding, the Aleutian Islands. 



Subsequent authors have noticed a remarkable change in the 

 character of the fauna in the neighbourhood of the Straits of 

 Fuca, the exit of Paget Sound, which would justify the sub- 

 division of Dall's Oregonian region into two nearly equal 



* For explanation of the Plate see p. 557. 



Proc. ZooL. Soc— 1915, No. XXXYIII. 38 



