ALCYONARIA — J. A. THOMSON AND DORIS L. MACKINNON. 665 



Order 11. ALCYONACEA, F^r^-z'// (pro parte). 

 Family ALCYONIDAE. 



Genus ALOYONIUM, Linne. 



ALCYONIUM (ERYTHROPODIUM) MEMBRANACEUM 



KiiKenthal. 



Ahyoniam memiranftcewm, Kiikenthal, Alcyonacea — Wiss. Ergeb 

 deutsch. Tiefsee Exped., xiii., 1, 1906, pp. 52-53, pi. 1., fig. 3, 

 p]. ix., figs. 42-44. 



Stations 42. 44, 34, 43, 47, 48. 



Numerous Gorgonid axes, e.g. of Ctenocella, are almost covered 

 Ijy Si^7npodium-\ike growths, "which investigation shows to be 

 creeping Alcyonids, agreeing on the whole, with Kiikenthal's 

 description of Alcyonium ( Erytliro'podium) metnhranaceum. The 

 ccenenchyma-spicules are very variable in form. There are 

 approximately spherical bodies (diameter •08-'12 mm.), short 

 thick cylinders with about two bands of thorny warts, forms like 

 cervical vertebrae, and others of more irregular shape. The 

 polyp spicules are spindles. Below the eight points of converging 

 spicules in the anthocodia there is a deep collaret of about eight 

 row.s of horizontally disposed slender spindles. The colour of 

 the colonies is light brown. 



This species presents considerable difficulties to the classifier. 

 In some specimens the Gorgonid axis is so completely and so 

 evenly ^erg^-own with the Alcyonid, that it is hard to believe 

 that one is not dealing with the natural coenenchyma. There is, 

 however, a slight tendency to the formation of " independent 

 stocks,'' and at the tips of the branches the encrustation often 

 forms a well-marked projection beyond the axis. On the more 

 weathered specimens it is instructive to note how the encrusting 

 Alcyouid is brought up sharply against large groups of Cinipedes, 

 Sponges, etc., which have also found the Gorgonid axis a suitable 

 place of attachment. 



In the majority of our specimens the internal structure could 

 not be made out with certainty, owing to their being in the dried 

 condition, and extremely friable. In the spirit-specimens, how- 

 ever, the coenenchyma shows the Alcyonid arrangement of side- 

 canals between the gastral cavities of the polyps, an arrangement 

 that, in Kiikenthal's opinion, removes these Sympodinm-hke 



