144 INVERTEBRATA. 



but that is a true Ceriopora (see Qoldfuss, Pet. Deutsch, pi. X. f. 7 d). 

 Moreover ours is a much more branching structure, rarely shewing 

 any tendency to fuse into a layer. From Heteropora ramosa it is 

 distinguished by its much more branched and bushy colony and by 

 its smaller cell openings. 



Its habit of growth distinguishes it readily from Heteropora 

 coalescens, Reuss, whose branches fuse together into an anasto- 

 mosing mass of stems. Sparsicavea irregularis, D'Orbigny, bears a 

 close resemblance to our species, but this also forms frequent anas- 

 tomoses, and its intermediate pores are fewer and less conspicuous. 

 In S. dichotoma, Hag., the colony is less branching and the cells are 

 much smaller. 



Localities. Up ware, Brickhill. 



HETEROPORA MAJOR, n. sp. 

 (Plate vii. fig. 18, a, b.) 



Description. Polyzoarium dendroid; the branches irregular, 

 tapering, in section circular or oval. Contiguous branches often 

 fuse and anastomose so as to form wall-like expansions. Cell 

 apertures numerous, simple, and small ; the peristome is plane with 

 the general surface. Intermediate pores few and small, irregularly 

 scattered. 



Affinities and differences. Distinguished from H. (Zonopora] 

 ramosa (Homer), and H. Icevigata, d'Orb., by the small size of its 

 cell openings, their wide separation, and the small, scattered inter- 

 mediate pores. The colony is larger than commonly occurs in H. 

 ramosa (about twice as big), and I have not detected the zonary 

 arrangement of the cells such as occurs in the two above-named 

 species. It is nearer to H. Buskana (de Loriol, Foss. Mont Saleve, 

 pi. XVIII. f. 6), but its stouter growth and the smaller size of its 

 cells serve to distinguish it also from this species. 



Locality. Upware. 



PORIFERA. 



Sponges. 



For a general account of the Sponges see ante, pp. 28, 29 (Indi- 

 genous fauna). 



