ANATOMY OF NEOHELIA PORCELLANA (MOSELEY). 



By EDITH M. PRATT, M.Sc, 

 The Owens College, Manchester. 



Plates LXII. and LXIII. 



Neohelia is a rare geuus belonging to the imperforate Madrepores. Duncan in his 

 Revision of the Madreporaria places it with two other genera — Baryhelia and Dihlasus 

 in the alliance Baryhelioida in the family Oculinidae. It is interesting in that it is 

 the onlj' living representative of the " alliance," the other two genera having only been 

 found fossil — Baryhelia in the cretaceous deposits in England and Europe, Diblasus 

 in the upper cretaceous deposits in England. Baryhelia forms a massive colony, and 

 Diblasus is encrusting, the colony being irregular in shape. 



The "alliance" that comes next to the Baryhelioida is the Lophohelioida, which 

 has at least two recent genera. It is clear from Fowler's description of Lophohelia 

 and Amphihelia that although there are certain general resemblances between the 

 two alliances as regards the anatomical characters of the soft parts, there is sufficient 

 difference to justify the retention of Duncan's classification. 



The genus Neohelia contains the single species N. poixellana, which was first 

 dredged by the Challenger Expedition off Api Island, New Hebrides, at a depth of 

 63 fathoms. Three specimens each encrusting the stem of a Gorgonid were taken, 

 and the genus and species subsequently described by Moselej' in his Report on the 

 Challenger Corals, p. 176, PI. X. figs. 7, 7a, 18S1. His account however is restricted to 

 a description of skeletal structures. 



In the collection of corals made by Dr Willey in the S. W. Pacific there 

 occurred a fragment of a colony of this species with the soft parts in a well preserved 

 condition. 



A superficial examination revealed the following points of difference from the 

 publi-shed description of the species : — 



1. All the Challenger specimens encrust Gorgonid stems. Our specimen is in 

 the form of an irregular hollow tube, and there is no evidence that this tube has 

 ever been occupied by a Gorgonid or other foreign support. 2. In his description, 



