212 ANNALS NEW YORE ACADEMY OF SCIENCES 



There can hardly be a doubt that the uuit of which the walls is constructed 

 is the cylindrical body with small tubular axis and oblique fibres or granuleb. 

 This structure may be interpreted as a small mesopore (the tubular axis) 

 and a wall beset with granules, but the interpretation here tentatively adopted 

 seems to be the more liliely. Stellate acanthopores, somejvhat comparable to 

 these, are figured by Ulrich in Buctropora simplex. 



Callocladia gen. nov. 



This type forms hollow cylindrical branches with the walls made up of one 

 or more layers. The walls of the zooecia are thin in the immature region, 

 much thickened in the mature region, with angular crests on the external sur- 

 face. Acanthopores are fairly abundant, showing clearly on the exterior, 

 rather obscure in thin sections unless the latter cut the walls where they are 

 thin, in which case' the acanthopores are striking and indent the cells. Me.so- 

 pores are abundant, usually in groups of two or more. Hemisepta are present. 



The superficial appearance of this organism is extremely suggestive of 

 Intrapora {I. hasalis and /. undulata) , but the mode of growth, not bi- 

 foliate but in the shape of hollow cylinders, and the undoubted presence 

 of acanthopores, etc., debars it not only from that genus but from the 

 same family. The mode of growth, the presence of acanthopores and 

 presence of hemisepta suggest a relationship with Cceloconus, in the 

 Ehabdomesidse, but the presence of abundant mesopores debars it from 

 that genus and all but debars it from that family. 



If the structures the nature of which is not clear but which are sug- 

 gestive of hemisepta can be interpreted as perforated diaphragms, this 

 form could find admission into the Batostomellidse with the relationship 

 probably closer to Stenopora than to the other members of the family. 

 The mode of growth as small, hollow, cylindrical branches having very 

 thin walls is rather alien to Stenopora, as is also the shortness of the 

 zocecial tubes and the increase by superposed layers, rather than by the 

 •extension of the tubes themselves. Mesopores are abundant — much more 

 so than in any species of Stenopora. Tabulae appear to be wanting or 

 extremely rare, which is also uncommon in Stenopora, while the walls 

 are strongly thickened in a solid mass, instead of by annulations. On 

 the external surface also, they have an angular crest which gives the cells 

 an appearance of being vestibulate. Acanthopores are rather more spar- 

 ingly developed than in most species of Stenopora. 



If the structures which suggest hemisepta have really that nature, 

 Callocladia would clearly be debarred from the Batostomellidas and would 

 probably find place among the Ehabdomesidae. 



Type, — Callocladia elegans. 



