REPORT ON THE ANTIPATHARIA. 25 



Lamarck made two species — one of the naked sclerobasic axis [Antipathes glaberrima), 

 and another of a specimen covered with ccenenchyma [Gorgonia tuberculata). Isolated 

 polyps have been named Palythoa denudata and Zoanthus sp. The leading points of 

 Lacaze Duthiers' investigation will be found under the genus Savaglia [infra, p. 51), and 

 I will here only mention those bearing on the systematic position of the species. In the 

 first place this form, for which Lacaze Duthiers creates the new genus Gerardia, has not a 

 spinose axis nor does its ccenenchyma contain spicules peculiar to it, but only those which 

 reach it from other forms and become adherent. It thus differs from Antipathidse in the 

 absence of spines. The sclerenchyma is thin and horny, and is primarily secreted around 

 the axis of some other form, usually one of the Muriceidse, so that the mode of branching 

 is not characteristic of the Gerardia, but of the particular species on which it becomes 

 parasitic. In older specimens where the stems and branches extend beyond the Gorgonid 

 basis, its growth becomes bushy. The polyps have twenty-four tentacles arranged in 

 two rows of twelve each, and each tentacle corresponds to an interseptal chamber as in 

 true Actiniaria. There is also a system of canals in the ccenenchyma, bringing the whole 

 of the polyps of a colony into communication. 



In his second memoir Lacaze Duthiers (45) gives an account of the structure of 

 Antipathes subpinnata and Antipathes larix, which have only six tentacles. Here too 

 he confirms the surmise of Dana, that the Antipathidse are closely related to the 

 Actiniaria. The mesenteries bearing reproductive organs, which Dana supposed to 

 exist, are described and figured by Lacaze Duthiers from living or fresh specimens. The 

 mesenteries are, however, unecpially developed. He describes six : two principal ones 

 bearing reproductive organs placed in a line parallel with the branchlet on which the 

 polyp is placed dividing it into two similar halves, and four others less fully developed 

 and destitute of reproductive organs, two in each lateral portion of the polyp. No 

 sections were made, but so far as could be made out no system of canals in the 

 ccenenchyma similar to those of Gerardia are visible externally, though Lacaze Duthiers 

 supposed them to be present. 



On account of these researches of Lacaze Duthiers, and the interesting morphological 



points which they bring out, the Sclerobasic Zoantharia have been divided by Yerrill (46) 



and others into two suborders: — 



GERAEDiDiE, with twenty-four tentacles and mesenteries, . genus Gerardia. 



Antipathid.e, with only six tentacles, . . . genus Antipathes, tyc. 



In 1868 Heller (50) recorded two species as occurring in the Adriatic, viz., Anti- 

 pathes subpinnata, Ellis and Solander, and Leiopathes glaberrima (Esper), both forms 

 already known from the Mediterranean. 



Verrill, in a review of the-Polypi of the East Coast of the United States (48), mentions 

 only two species, Antipathes boscii, Lamouroux, collected by Agassiz, near Charleston, 

 and Antipathes alopecuroides, Ellis and Solander, the latter on the authority of Elks. 



(ZOOL. CHALL. EXP. PART LXXX. — 1889.) LM i 



