142 THE VOYAGE OF H.M.S. CHALLENGEE. 



manner. The polyps are completely retractile, there is no circlet of spicules at the base 

 of the tentacles, and there are no spicules in the tentacles. When the polyps are with- 

 drawn, the tentacles invaginate, their bases forming. a central knob-like mass, the upper 

 walls of the mesenterial chambers, which when the tentacles are infolded become inflated, 

 forming an eight-rayed frill, next sink in, forming a series of eight depressions wliich 

 extend from the bases of the tentacles to the external body-wall of the polyp. The 

 spicules are for the most part spiny spindles, with numerous pink stellate forms and a 

 few club-shaped forms with attenuated foliaceous expansions. 



Pseudoplexaura crassa (Ellis and Solander) (PI. XXXIII. fig. 3). 



Gorgonia crassa, Ellis and Solander, The Natural History of many curious and uncommon 

 Zoophytes, &c., p. 91, 1786. 



It is with a great deal of doubt that a series of large fragments, dredged in shallow 

 water at the Bermudas, is referred to this .species. The original dcscrijjtion is as follows: — 

 " Gorgonia teres dichotoma, ramis crassis virgatis divaricatis ascendentibus, carne violacea 

 crassa, osculis prominulis sequi distantibus, polypos octotentaculatos marginibus cirratis 

 exserentibus, osse subfusco corneo," and " this Fleshy Gorgon is round and dichotomus 

 with long fleshy branches, which bend a little out and then grow upright. The flesh is 

 of .a violet colour, plump and full of little rising mouths, disposed on the surface near one 

 another and at equal distances, these send forth polypes with eight claws, these have 

 small fibres on each side. The bone is of a dark brown colour like horn." The specimen 

 described was preserved in spirits, and the remark is added that " the flesh is very thick 

 and the bone very small at the extremities ; in large old specimens the bone is very 

 black and like horn." We are thus particular, as VerrilP records a species from the same 

 locality under this name which he thinks agrees perfectly with the description of Ellis. 

 In his remarks on this agreement Verrill quotes Ellis as describing the arrangement of the 

 cells as " scattered," whereas it will be seen from the above quotation that Ellis describes 

 them as " disposed near one another and at equal distances." 



Verrill gives Gorgonia porosa, Esper, Gorgonia a7itipathes, Esper, and Gorgonia 

 vermiculata, Lamk., as synonyms of this species, but an examination of these species 

 shows marked diff'erences between each of them, and that they are not even very closely 

 related to this form ; Plexaura porosa (Esper) has a well-marked layer of foliaceous 

 and one-sided spiny clubs. Plexaura antipathes (Esper) is easily distinguished by its 

 spiny spheres and branching spiny spindles, while Gorgonia vermiculata, Lamk., is 

 a Plexaurella. 



The colony is feebly branched, mostly in one plane. The height of the various 

 fragments collected, apparently torn from the one base, varies from 150 to 225 mm., with 

 a basal diameter of 8, 10, and 12 mm. respectively, which tapers to one of 4 mm. at the 



' Bull. Mus. Comp. Zool., 1865, vol. i. p. 34. 



