390 ESCHARIDiE. 



leaving the general question as to the grouping of the 

 Reteporine forms to be settled after a more extended 

 study of their structure and morphology than is possible 

 within the limits of our Fauna. 



Smitt has dismembered the genus Hetepora^ and has 

 placed our H. Beaniana in his genus Eschara as the com- 

 panion of Porella compressa, Porella lavis, and other 

 species. In this determination I am quite unable to 

 agree Avith him^ as, besides other differences, R. Beaniana 

 seems to me to depart widely from the zooecial type of the 

 genus Porella. 



It may be remarked that amongst a considerable pro- 

 portion of the species which have been hitherto ranged 

 under the genus Reteporn there is a large amount of 

 general agreement , apart from any consideration of the 

 minuter details, or the mere peculiarity in the branching ; 

 they have many salient features in common, and leave on 

 the mind o£ the student the impression of strong affinity 

 as- existing amongst them. The mode of origin and the 

 general character of the zoarium seem to be much the 

 same in all of them ; the existence of avicularia on the 

 dorsal surface is a very usual character; these appen- 

 dages are exceptionally numerous, and their prevalent 

 forms are similar to a large extent ; the fissured ovicell is 

 commonly (though not universally) present. It is possible 

 that in these and other characteristics we may have the 

 indications of a natural group, under which the various 

 modifications in the structure of the orifice &c. which 

 actually occur may be properly ranged. But the mate- 

 rials for a judgment on this point are at present wanting. 



