BRYOZOA. 115 



q. Apertures small, with elevated generally oblique peristomes. 



XCV. Diamesopora. 



D. Zoarium bifoliate, an explanate frond S+- 



5J Mesopores present, frond not articulated 15*. 



15* Mesopores tabulated LXXIX. Coscinella. 



15* Mesopores not tabulated LXXVII. Stictoporella. 



5 J Mesopores absent 16*. 



16* Articulated basally, vestibules separated by thick walls. 



LXXV. Clathropora. 

 16* Not articulated, interzocecial spaces with vesicular tissue. 



L'XXXVI. Coscinium. 



D. Zoarium bifoliate ; not explanate. 6J. 



6j Zoarium jointed or articulated at least at the base 17*. 



17* Apertures arranged in longitudinal series 19. 



19. Simple unbranched, lanceolate or falciform frond with basal 



articulation LXXIII. Ptilodictya. 



19. Bushy, of numerous articulating equal segments spread in a 

 plane LXXVI. Arthropora. 



19. Segments from cylindrical root, two buds from truncated end 



of preceding LXXXVII. Acrogenia. 



17* Apertures in decussating series surrounded by sloping hexagona. 



areas LXXIV. Escharopora. 



6J Zoarium not articulated 18*. 



1 8* Mesopores present 20. 



20. Mesopores tabulated .' r. 



r. Zoarium ramose, compressed, divided dichotomously. 



LXXVIII. Intrapora. 



20. Mesopores untabulated LXXVII. Stictoporella. 



18* Mesopores absent 21. 



21. Branches bifurcating, straight edged with parallel or sub- 



parallel margins s. 



s. With well marked lunarium, nearest to the margin. 



LXXXIII. Cystodictya. 



s. Without lunarium LXXX. Rhinidictya. 



s. Without lunarium, with maculae LXXXII. Pachydiciya. 



s. With strong central ridge making section somewhat rhombic. 



LXXXV. Taeniopora. 



21. Branches an irregular explanate frond t. 



t. Apertures subelliptical ; thin bifoliate expansions, surface 



with solid maculae LXXXIV. Dichotrypa. 



t. Apertures semi-elliptical, with broad triangular space be- 

 neath each aperture XCIII. Worthenopora. 



t. Apertures with eight to ten vertical septa-like ridges. 



X C 1 1 . A ctin try pa . 

 t. Apertures oblique, with posterior edge lip-like. 



LXXXI. Phyllodictya. 



1). Zoarium of prismatic branches triangular in cross-section 7J. 



7j Branches triangular, with faces crossed by transverse ridges. 



LXXXIX. Scalaripora. 

 Jl Faces of triangular branches without transverse ridges. 



LXXXVIII. Prismopora. 



