Rev. T. Hincks on British Polyzoa. 529 



with his suggestion, and to avoid confusion, I have assigned 

 this name to L. vionodon. 



Many other distinct groups are blended in the genus 

 Lepralia of authors ; I merely give the foi'egoing as a sample 

 of the work of redistribution which has to be done, and must 

 reserve the more complete treatment of the subject for some 

 future opportunity. 



The genus Memhraniyora also includes a large number of 

 species ; but there seem to be few distinct types of structure 

 amongst them. 



1. MiCROPORA, Gray. 



{Memhranipora^ part, Busk. 

 Lepralia, part, Norman, &c.) 



Zoarium incrusting ; zoocecia with prominent raised mar- 

 gins ; front depressed, wholly calcareous ; oral aperture semi- 

 circular, enclosed by a calcareous border. 



Brit. spec. Memhranipora coriacea, Esper. 

 Lepralia complanata, Norman. 



2.- Setosella, nov. gen. 



(Metnhrampora, part, Busk. 

 Cupularia, part, Smitt.) 



Zoarium incrusting ; zoocecia with raised margins ; front 

 depressed and wholly calcareous ; aperture semicircular ; 

 vihracular cells alternating with the zoocecia throughout the 

 colony ; vihracula setiform. 



Type Memhranipora vulnerata, Busk. 



3. Megapora, nov. gen. 

 (Lepralia, part, Busk.) 



Zoarium incrusting; zoocecia with prominent raised mar- 

 gins ; front depressed, wholly calcareous ; oral aperture tri- 

 foliate ; oral valve composed of two portions, a fixed trans- 

 versely elongate lamina and a movable lip. 



Type Lepralia ring ens ^ Busk. 



Suborder Ctenostomata, Busk. 



Smitt has pointed out that the principal character on which 

 this suborder is founded, the operculum of sekc, occurs occa- 

 sionally amongst the Oheilostomata and is not absolutely 

 distinctive. Ehlers questions the validity of this division, 

 and proposes to dismember it, by separating the fleshy forms, 

 Halcyonellea, Ehrenb. {AlcT/onidium, &c.), from the Vesicu- 

 lariidco. The latter he would constitute a distinct group, 



Ann.de Mag. N. Hist. Ser. 4. Vol. xx. 36 



