REPORT ON THE ALCYONARIA. 143 



slightly knobbed terminations. Branches arising very sparingly from the presumably 

 main stems. Axis horny, with a calcareous centre and calcareous particles interspersed. 

 Polyps crowded in a somewhat spiral manner on the stems and branches ; projecting 

 very slightly from the level of the ccenenchyma, but sufficiently so to give a papilliform 

 appearance to the colony. The polyps and tentacles are retractile ; the upper walls of 

 the eight mesenterial chambers, when the polyps expand, become inflated and form a 

 circlet of little flaps around the base of the tentacles, these inflations are somewhat 

 pouch-shaped and resemble an outer circlet of simple frill-like tentacles ; on the tentacles 

 becoming withdrawn, these inflations are infolded and in the dried specimen become 

 depressed, so as to give the appearance of eight depressions around the central portion of 

 the polyps (the chambers seem to communicate by pores with the exterior). The polyps 

 are 1"5 mm. in their broadest diameter. The ccenenchytna is thick and tough (friable 

 when dried), the outer layer is white and semimembranous, with but few spicules and 

 these colourless ; the inner layer is packed with purple or violet coloured spicules ; this 

 dense layer sometimes shows through the outer layer. The numerous nutrient canals 

 surround the axis. 



There are no spicules in the tentacles nor at their bases. Those in the outer layer of 

 the ccenenchyma are colourless spiny spindles, and a few club-shaped forms ; in the 

 inner layer the coloured spicules are either crosses or few-rayed spindles ; the following 

 are the measurements. Colourless spiny spindles — O'52-O'l ; 0"56-0*l ; 0'30-0*04; 

 0-82-0-12 mm.; club-shaped forms 0-3-0-1 ; 0-32-0-18 ; 0-4-0-16 mm.; pink spindles 

 0-2-0-12; 0-34-0-14; 0-32-0-12 ; O-lS-O'l ; O-IG-Oa ; 0-14-0-1 ; 012-0-05 mm.; 

 pink crosses 0-12-0-08 ; O'lG-O-l ; 0-24-0-1 mm. 



Habitat. — Bermuda ; shallow water. 



Genus Enplexaura, Verrill. 



Evplexaura, Verrill, Proc. Essex Inst., vol. vi p. 74, 1869. 



Verrill' in 1865 referred a species from the Cape of Good Hope to the genus Plexaura 

 as Plexaura friabilis, Lamk. Although it possibly might have been in part known to 

 Lamouroux, it is certainly not the Plexaura friabilis of Milne-Edwards and other modern 

 writers, because this latter proves to be a Plexa,urella. For this form Verrill afterwards 

 made {loc. cit.) the genus Enplexaura, naming the species Euplexaura capensis. 



The spicules diff'er widely from those of Plexaura, and although in some respects 

 they approach those of Plexaurella, yet they would seem to differ as widely from these 

 as they do from Plexaura. " In external characters it resembles Plexaurella, with 

 rather large, open cells. The spicula are mostly short, stout, blunt, warty spindles, of 



• Bvll. Mus. Comp. ZooL, vol. iv. p. 186. 



