550 Mr. H. N. Moseley on the true 



these masses by broad bases, and were all remarkably small, no doubt 

 from the unfavourable condition in which they existed on a volcanic 

 bottom. 



The largest of the series of 30 specimens of the curved variety of C. 

 clavus measured 2 centims. in height. The soft parts of the animals 

 were transparent and almost colourless. 



Acantlwcyathus, sp. 

 Obtained off Kadavu, Fiji Islands, August 3, 1874, in 210 fathoms. 

 The specimen appears to be closely allied to A. Grayi as described by 

 Milne-Edwards*. It differs in beiug attached, not free ; but the pedicle 

 of attachment is very fine. A. Grayi has its lateral costae provided with 

 three or four spines, very strong, horizontal, and compact. In the 

 present specimen the spines are developed only on one of the lateral 

 costae, and indicated by indentations on the other. The calicle is oval 

 in horizontal section, as in A. Grayi. Three species of Acantlwcyathus 

 have been described, viz. A. Grayi, recent, locality unknown ; A. Has- 

 tingsce, of Miocene age, from Malta (M.-Edw. & H., 1. c.) ; and A, 

 spiniger, recent, from Japan, lately described by Saville Kent t. 



Trocliocyatlius coronatus (Pourt.). 

 The corallum is white. It is free, but with a small scar of adherence. 

 It is circular in horizontal section, with a broad flat base, with the plane 

 of which the walls of the calicle, sloping outwards, make an angle of 

 about 60°. At the junction of the wall of the calicle with the base, the 

 base is continued horizontally outwards into twelve stout spines, irre- 

 gularly beset with small pointed tubercles. The spines correspond in 

 position with the primary and secondary costae. There are six systems 

 of septa, and four cycles, with a partial fifth cycle in large specimens. 

 The septa of the four cycles are complete. All the septa are exsert. 

 The primary, secondary, and tertiary septa bear pali, those of the tertiary 

 septa being the most developed. The columella is large and composed 

 of a tubercular mass of contorted papillae. The largest specimen 

 measures 27 millims. in diameter of the calicle, and 32 millims. in 

 extreme diameter between the tips of the exsert septa. Its extreme 

 height is 20 millims. 



Eive specimens of this coral were obtained off St. Thomas, D. W. I., in 

 390 fathoms. One of the specimens, being very young, was seen to be 

 identical with the young and imperfect specimen figured and described 

 by Count Pourtales as T. coronatus t. The young form differs very 

 much from the adult, the spines being scarcely at all developed. In its 

 tendency to develop a fifth cycle of septa this species conforms with the 

 Trochocyathi armes of MM. Edwards and Haime, a large number of these 



* MM. Milne-Edwards et J. Haime, ' Hist. Nat. des Coralliaires,' t. ii. p. 22. 



t W. Saville Kent, "On new Madrepores," Proc. Zool. Soc. 1871, p. 275. 



\ Pourtales, I, c. p. 15. 



