94 



Mr. H. N, Moseley on the 



[June 15, 



the tissues, and takes the place of the hard calcareous supporting struc- 

 tures which have been removed by the acid. The sections are mounted 

 in glycerine, and the imbedding subatance, which is left in situ in the 

 sections, becomes perfectly transparent, in fact almost invisible in this 

 fluid. I stain the decalcified corals with carmine, then soak them in gly- 

 cerine, and then transfer them directly to the warm fluid jelly, instead 

 of treating them first with absolute alcohol after staining, as does Miha- 

 kowics. A teaspoon heated in hot water is a most convenient instrument 

 for transferring the small masses of tissue, with the fluid jelly, to the 

 cavities in the hardened liver used as an imbedding base. I have dwelt 

 upon this method because it seems to me likely to be one which will 

 prove o£ the greatest service in all kinds of difiicult histological problems, 

 such as Corti's organ, early stages of embryos, retina, &c. It is quite 

 possible by the method to obtain sections of a single hydroid sporosac or 

 planula. 



The Stylasteridao obtained off the Eio de la Plata comprised six genera, 

 viz. : — Stylaster ; Cryptolielia • Allopora ; Errina ; a new genus, Polypora ; 

 and a further new genus allied to Errina, which I propose to term 

 Acanthopora. There is much confusion as to the determination of 

 even the genera of the Stylasteridse, and I have found it impossible 

 to determine species in the absence of specimens for comparison. The 

 Stylaster appears probably to be S. erubescens of Pourtales*. The 

 CryptoTielia is the same as that obtained all over the world by the 

 * Challenger ' in deep water, and apparently not specifically distinct 

 from (7. pudicaf. Of the AUopora I cannot determine the spe- 

 cies. There is one coral which appears to belong to the genus Errina, 

 GrrayJ, of which a further diagnosis is given from the type specimens 

 by Saville Kent §, and one of the allied new genus Acanthopora, The 

 whole of the classification of the Stylasteridae will need revision on the 

 more certain basis of the knowledge of the structure of the soft parts. 

 In the older regions of its stem Lepidopora appears to assume the 

 character of a Stylaster, The coral for the reception of which I 

 form the new genus Polypora differs markedly from other members of 

 the family; I at first took it to be a MiUepora with unusually large 

 zooids. 



The genus may be thus characterized, as far as the hard parts are con- 

 cerned : — 



Genus Polypora. 

 Corallum pure white, composed of a finely reticular but compact 

 coenenchym. It forms single, stout, vertical stems, usually compressed 

 from before backwards, so as to be oval in transverse section. The stem 

 gives off a limited number of irregularly dichotomous branches, which 



* Illustrated Catalogue of the Museum of Comparative Zoology at Harvard College. 

 No. IV. Deep-Sea Corals. By L. F. de Pourtales. Cambridge, Mass. 1871, p. 34. 

 + Hist. Nat. des Coralliaires, par. MM. Milne-Edwards et J, Haime, t, ii. p. 127. 

 I Proc. Zool. Soc. 1835, p. 35. § Proc. Zool. Soc. 1871, p. 283. 



