XORTH AMERICAX ALCYONARIA. 549 



described by Koelreuter, and measurements and illusti^ations of 

 the spicules of Paragorgia nodosa — which does not seem to me a 

 distinct species — are given by Koren and Danielssen, there is no 

 good modern description either of the genus or species. 



The genus, however, seems to be quite well distinguished from 

 others of the same family by the very well-marked dimorphism 

 of the zooids and by the characters of the spicules. The occur- 

 rence of dimorphism in the genus, first recorded by myself in 

 1883, is of importance because it is of only exceptional occurrence 

 in the Pseudaxonia, and can be clearly determined, not only in 

 fresh and spirit specimens, but also in specimens that have been 

 dried for many years. 



The geographical distiibution of Paragorgia arhorea cannot be 

 very accurately determined from the literature. It is probable 

 that some of the specimens from the Mediterranean Sea and 

 Atlantic Ocean, refered to Alcyoniutn arhoreum by the older 

 naturalists, belonged to a difierent genus or species. Of recent 

 years there is no record of any specimens being found outside 

 the area of the ISTorwegian coasts. It was not found by the 

 ' Challenger ' Expedition in the Atlantic, nor is it recorded from 

 the deep water off the west coast of Ireland by the Irish 

 Fisheries Investigations. 



It was therefore with some surprise that I found, in the collec- 

 tion sent to me by Mr. Fraser from tlie Gulf of Alaska, a 

 specimen that was clearly a species of Paragorgia. For com- 

 parison with the Alaskan specimen I have examined a specimen 

 of P. arhorea from the Trondhjem Fjord, and I have no hesitation, 

 after making this comparison, in placing the two specimens in 

 the same species. 



The specimen is probably only a fi'agment of a large colony, 

 but it shows'a simple bifurcation at the distal end. It is 

 170 mm, in length. The stem at the base is oval in section 

 (1.4x18 mm.). As in the specimen from Norway, the stellate 

 pores of the autozooids are scattered irregularly in clusters all 

 round the stem, many of the clusters being mounted on dome- 

 shaped prominences from the surface. The pores of the siphono- 

 zooids are numerous, quite irregularly distributed, and easily seen 

 with a hand-lens. The axial part of the stem is creamy-white in 

 colour, and is penetrated by canals corresponding in arrangement 

 with those in my specimen of the type-species. The crust, or 

 outer layer, of the stem is about 1 mm. in thickness, and is 

 distinguished by its brick-red colour. 



The spicules of the autozooids are irregularly tubercidated 

 spindles, of which the larger ones are about 0-25 mm. in length. 

 These spicules are probably distributed in the tentacles or body- 

 wall of the anthocodise of the autozooids, but I cannot, determine 

 this with certainty. 



The spicules of the coenenchym and axial region are double 

 stars of the type shown in Kolliker's ' Icones,' pi. xviii. fig, 45. 

 They are of nearly constant size, 0'07 mm. in length. 



