1871.] MR. W. S. KENT ON NEW MADREPORES. 277 



coe.nenchyma, indicate its true position among the representatives 

 of the genus Amphihelia of the same author, to which genus 

 I here refer it while proposing the following more exhaustive specific 

 diagnosis : — 



Corallum arborescent, irregularly branching, subflabellate. Ccenen- 

 cbyma faintly striate, frequently coalescing, somewhat fistulose ; 

 greatly developed in the trunk and main branches, but almost 

 entirely wanting in the ultimate ramifications. Calices infundi- 

 buliform, increasing by alternate distal gemmation, two gemmae, 

 however, occasionally springing, as in Ci/athohelia, opposite each 

 other from the margin of the same calice. Septa 24 in number, 

 forming three complete cycles ; the primaries more exsert than the 

 secondaries, and the latter slightly more so than the tertiaries, pro- 

 jecting but little into the calicular fossa, to which they consequent!)* 

 give the " internal striate " appearance observed by Lamarck. 

 Costa? only visible superiorly. Height of corallum several inches. 

 Diameter of calices y 1 ^ inch. 



Hab. Formosa, Indian seas. B.M. 



Stenohelia maderensis, nobis. (Plate XXIV. figs. 3, 3 a, b, c.) 



AUopora maderensis, J. Y. Johnston, Proc. Zool. Soc. 1862, 

 p. 196, figs. 1,2, 3. 



Stenohelia maderensis, W. S. Kent, Ann. & Mag. Nat. Hist. v. 

 p. 120, 1870. 



I avail myself of the opportunity of giving here an illustration of 

 this interesting species, first introduced by Mr. Johnston, but whose 

 characters and structure are by no means satisfactorily explained or 

 displayed in the description and figures accompanying his com- 

 munication. 



Since the publication of my paper above quoted, in which I 

 make this form the type of a new genus, I have, through the kind 

 courtesy of Prof. Du Bocage, examined additional specimens belong- 

 ing to this same species contained in the Lisbon- Museum collection, 

 obtained from the Cape- Verde Islands, and having the ampulla}, pre- 

 sent in the British-Museum example, still more highly developed. A 

 fragment in illustration of this is represented at Plate XXIV. fig. 3a. 



Stylaster amphiheloides, n. sp. (Plate XXIV. figs. 1, 

 1 a, b, c.) 



Corallum branching, subflabellate ; basal ccenenchyma often fis- 

 tulose and coalescing, its surface smooth. Calices increasing by 

 alternate distal gemmation ; calicular fossa deep. Columella styli- 

 form, echinate, deeply immersed. Septa even, twelve to sixteen in 

 number, projecting but little into the calicular fossa, often coalescing 

 laterally, and so forming an inner tube, and giving the interseptal 

 chambers a punctate appearance, as in S. erubescens (Pourtales) 

 and various species of Allopora. Ampullte rudimentary, represented 

 by a few raised points scattered irregularly over the surface of the 

 ccencuchyma, but more particularly in the neighbourhood of the 

 ultimate ramifications. 



