126 THE CRAG POLYZOA. 



Habitat. C. Crag, Sutton, S. Wood; Cretaceous, D'Orbigny ; (?) Goldfiiss. 



Though not much inclined to adopt any of M. D'Orbigny's species, about which, at 

 any rate, the doubt always exists whether they are his own or not, his figures above cited 

 leave so little doubt of their representing a form identical with the Crag fossil, that I 

 have no hesitation in referring them to the same species. 



With respect to the synonym cited from Goldfiiss, as there are no means of judging 

 correctly with respect to the Heteropora really intended by him, except what are afforded 

 by his very defective figures, it is impossible to determine whether the present species is 

 represented in his plate or not. All that can be said is, that the external resemblance, 

 and the apparent zonular disposition of the cell-orifices, would lead one to suppose that it 

 may be so. 



In the same way that the preceding species might be regarded as intermediate 

 between Hornera and Heteropora, so may this be looked upon as a link between these 

 two genera and Cricopofa, and perhaps as affording an additional proof of the artificiality 

 of the not very satisfactory classification we are at present compelled to adopt of these 

 Polyzoa. 



The distinctive specific characters are found in the partially pitted and partially fibro- 

 reticulate condition of the surface ; the peculiar zonular disposition of the cell-orifices ; 

 the curious wavy formation of the cell-walls, which is well shown in PI. XIX, fig. 5 ; 

 and the smallness or shortness of the interstitial pores and canals. 



Genus 13. HETEROPORELLA (n. 



Polyzoario disciformi et adnato, sive incrustante et indefinite ; superficie porosa, aper- 

 turis cluplicis generis ornata ; orificiis nernpe cellularuin, et ostiolis interstitialibus. 



Polyzoarium discoid and adnate, or indefinite and incrusting; surface uniformly 

 porous, with openings of two distinct kinds. 



REPTOMULTICAVA (?), IfOrbiyny. 



The relations of this genus have been noticed in the remarks appended to the account 

 of Heteropora, with which the present agrees in all respects except its habit. In 

 Heteropora the growth is erect, and usually, though not always, branched, whilst in 

 Heteroporella it is expanding and discoid, or indefinite and iucrusting; the one, in 

 fact, standing in the same relation to the other that Lcpralia does to Eschara. Conse- 

 quently, the same explanation with respect to the two kinds of pores will apply to 

 Heteroporella as was offered in the case of Heteropora. 



