REPORT ON THE ALC YON ARIA. xliii 



2. Ceratoisis, Perceval Wright, Ann. and Mag. Nat. Hist., December 1*868, p. 427, 



January 1869, p. 23 ; Gray, Cat. Lithophytes Brit. Mus., 1870, p. 18 ; Studer, 

 Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, Bd. xi. p. 10, July 1883. 



The colony is simple or branched, in the latter case with branches arising from 

 the calcareous internodes. These latter are long, and hollow when young. The 

 ccenenchynia contains long, smooth spindles or needle-like spicules. In the polyps, 

 which are non-retractile, there are large needles. One row of these spicules is so 

 disposed, that one of them lies at the base between each pair of tentacles and projects 

 beyond them, the result being a circlet of diverging spines round about the oral region. 



[Lepidisis, Verrill, Bull. Mus. Comp. Zool., vol. xi. pp. 10, 18, 1883. 



The colony is simple or branched. The branches arise from the horny nodes. The 

 ccenenchynia includes an outer layer of small, elongated, scale-like spicules, sometimes 

 intercalated with small spindle-shaped spicules. The large polyps exhibit at the base of the 

 tentacles eight large needle-like spicules alternating with the tentacles; the polyp-walls 

 include large spindle-shaped spicules, more or less covered by an outer layer of small 

 elongated scales. 



It seems difficult to separate the unbranched species of this genus from the unbranched 

 species of Ceratoisis. In Ceratoisis also and indeed in the typical forms of Wright and 

 Studer, the coenenchyma also includes scale-like flat spicules. The predominance of these 

 over the long needles leads to forms where the coenenchyma is externally smooth and thick, 

 as for instance in Ceratoisis grandijlora, Studer. The polyps, however, are in both 

 cases of similar structure. It is perhaps advisable provisionally to unite Lepidisis and 

 Ceratoisis^^ 



3. Callisis, Verrill, Bull. Mus. Comp. Zool., vol. xi. p. 9, July 1883. 



The colony is branched ; the calcareous internodes of the axis are solid or very slightly 

 hollow; the branches spring from the calcareous internodes. The short polyps contain 

 spindle-.shaped spicules. The coenenchyma is furnished with a layer of flat, scale-like 

 spicules. 



4. Acanella, Gray, Cat. Lithophytes Brit. Mus., 1870, p. 16; emend. Verrill, Bull. 



Mus. Comp. Zool., vol xi. p. 21, 1883. 



The axis of the colony may be simple or branched. The axis has long calcareous 

 internodes and short horny nodes. The branches arise from the nodes, often in whorls. 

 The coenenchyma is thin, with long spindle-shaped spicules, which form a circlet of 

 needles around the base of the tentacles. The tentacles contain numerous spicules. 



