104 THE CRAG POLYZOA. 



the sulci usually diverging obliquely from an imaginary median line, and finely punctate ; 

 surface between the sulci smooth or subgranular. 



HORNERA STRIATA, M. Edwards, 1. c., p. 21, pi. xi, fig. 1 ; Michelin, Icon. Zooph., p. 316, 

 pi. Ixxvi, fig. 7. 



Habitat. C. Crag, S. Wood ; Doue, Michelin. 



11. H. RHOMBOI0ALIS (. sp.) PI. XV, fig. 4. 



Ramis cylindricis, furcatis. Superficie anteriori reticulata, posteriori granulosa vel 

 rugosa, seriebus punctorum obliquis ornata. Cellularura orificiis orbicularibus, peristomate 

 paullulimi incrassato marginatis, porumque supra gerentibus. 



Polyzoarium composed of cylindrical, forked branches ; anterior surface strongly and 

 regularly reticulate ; mouths of cells orbicular, border annular, slightly thickened, a pore 

 above each ; dorsal finely granular or rugose, punctured in oblique rows. 



Habitat. C. Crag, S. Wood. 



Genus 2. IDMONEA, Lamouroux. 



Polyzoario rainoso ; ramis plerumque dichotomis liberis, vel subinde conjunctis ; postice 

 rotundatis, antice carinatis. Cellularum orificiis, in seriebus alternis, transversis vel 

 obliquis et in carina media angulatira conjunctis dispositis. 



Polyzoarium ramose, branches dichotomous or irregularly divided ; free or anasto- 

 mosing ; mouths of cells disposed in parallel, transverse or oblique, usually alternate, rows, 

 on each side of the front of the branches, which is angular or carinate in the middle. 



IDMONEA, Lamx., Exp. Meth., p. 80, 1821 ; Defiance ; Dlainville ; M. Edwards; Johnston; 



Lonsdale ; Reuss ; Michelin; Hugenow. 

 IDMONEA (pars), Earner ; ])' Orligny . 

 RETEPOKA (pars), Lamarck; Goldfuss ; Hagenow. 



RtTICULIPORA, CRISINA, STICHOPORA, TUBIGERA, SATEROCATA, SEMICELLAKIA, D' Orbigny . 



1. IDMONEA PDNCTATA, D'Orbig. (sp.} PI. XV, fig. 5 ; PI. XVI, fig. 3. 



Polyzoario ramoso sen fenestrato ; ramis subcylindricis ; cellularmn orificiis parvis, 

 orbicularibus, prouiiiiulis, 3 4 singulis in seriebus. Superficie anteriori, posteriorique 

 puuctata. 



