BRITISH MARINE GENERA 53 I 



Colony glistening. Orifice much obscured by the mucro and by 

 stout spines developed from the peristome. Tooth (concealed in 

 old zooecia) large, strongly curved to one side. 



Rhynchopora (Rhynchozoon l ) bispinosa 



Tooth of the lower margin of the orifice symmetrical, sometimes bifid. 

 Avicularia may be present laterally, but are not developed on the 

 mucro .... Mucronella (Fig. 255, A) 



f Orifice at least half the width of the zooecium, bordered below by a 



well-developed prominence or " umbo." Surface of the zooecium 



62. 1 strongly areolated round the margin . . Umbonula 2 



Orifice considerably less than half the width of the zooecium. 



{ Schizoporella (Fig. 239, B) 



Cyclostomata. 



63. 



' Colony erect. Branches of two or one series of zooecia, divided at 

 intervals by chitinous joints. Ovicells pear-shaped. 



. Crisia (Fig. 237) 

 Colony erect, unjoin ted . . . . .09 



Colony in the main adherent ; or circular ; or lobed . .64 



I Colony more or less circular, discoidal or cup- shaped, sometimes 



64. - forming secondary colonies by marginal budding . .65 



Colonies not circular . . . . . .68 



65. 



f Zooecia separated by calcified interspaces, which may contain large 



pores, often difficult to distinguish from the orifices . 66 



1 No large pores as above. Orifices not spiny. Zooecia nearly always 



pores, often difficult to distinguish from the orifices . 66 



large pores as above. Orifices not spiny. Zooecia nearly always 

 contiguous, except where an ovicell is developed . .67 



Colony composed of one or more convex discs, bearing radial ridges, 

 each composed of many zooecia . . . Domopora 



Colony encircled by a thin calcareous lamina, which gives rise to new 

 zooecia, its centre usually devoid of zooecia when adult, and often 

 bearing the orifice(s) of the ovicell. Zooecial orifices often spiny. 



Lichenopora 



Zooecia with a long, tubular, free portion, in some cases curved in a 

 horizontal plane. Colony fan-shaped until a late stage. 



Tubulipora flabellaris 



Tubular portion absent, or for the most part curved in a vertical 

 plane. Some of the orifices may be closed by a calcareous plate. 

 Colony circular or bluntly lobed . . . Diatfopora 



1 Hincks, "Marine Polyzoa" (reprints from Ann. Nat. Hist. 1880-91), Index, 

 p. v. note. (Replacing Rhynchopora, preoccupied for a Brachiopod.) 



2 A form of Lcpralia pallasiana, in which a mucro is developed, may be mistaken 

 for Umbonula (see characters given for Lepralia under No. 59). 



