ON FOSSIL POLYZOA. 171 
Family VI. HeETEeRoporip2. 
In this family, further on, I shall include -the whole of the Fossil 
Polyzoa which have two sorts of openings on the surface, ‘cells’ and 
‘ostioles.’ They are not a large group, but the species have distinct 
characters. 
I have already pointed out the varied sources of information re- 
specting Heteropora (‘ Brit. Assoc. Rep.’ mihi, 1882, Fossil Polyzoa), 
both recent and fossil. Since this was written Mr. Ulrich in his 
‘American Palzozoic Bryozoa’ has published descriptions of Heteroporu 
from the Chalk of Arkansas, and I have been furnished by Mr. J. M. 
Nickles with specimens of Mr. Ulrich’s species, and I cannot help re- 
marking that there is a wonderfully close correspondence between the 
American and the British Cretaceous forms, so much so that it is difficult 
to distinguish between them. 
Genus Herrropora, Blainville. 
‘Zoariwm erect, cylindrical, undivided or branched, surface even, 
furnished with openings of two kinds; the larger representing the 
orifices of the cells, and the smaller the ostioles of the interstitial canals or 
tubes.’—Busk, ‘ Crag Polyzoa,’ p. 120. (For synonyms see Busk.) 
HerTEROPORA DIcHoTOMA, Goldfuss. 
= Ceriopora dichotoma, Goldfuss, ‘ Petrifac. Germ.’ p. 54, tab. 10, fig. 9 f. 
= Heteropora dichotoma, Blainv. ‘ Man.’ p. 417. 
* al Morris, ‘ Cat. Brit. Foss.’ 
As Mr. Busk remarks (‘Crag Polyzoa,’ p. 126): ‘There are no 
means of judging correctly with respect to the Heteropora really intended 
by Goldfuss, except what are afforded by his very defective figures.’ 
The several species described by Mr. Busk in the ‘ Crag Polyzoa’ have 
the merit of being exact on minor details, and they are well illustrated, 
but there is one remark that I cannot resist directing attention to before 
describing the British Cretaceous Heteropora. In speaking of H. re- 
ticulata, Busk (unfortunately no figure is given of this species), the author 
says (p. 125) : ‘ The peculiar characteristic of H. reticulata is the coarsely 
sulcate or reticulate aspect of the surface, which bears, in some respects, 
a strong resemblance to that of a Hornera, whence, as well as from the 
smallness of the interstitial pores and canals, this species may be regarded 
as intermediate between Hornera and Heteropora.’ And Mr. Busk regards 
the species described as H. levigata ? D’Orb. (‘Crag Polyzoa,’ pp. 125-6) 
as a probable link between these two genera and Oricopora, ‘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.’ ) 
As I have carefully worked over the Heteropora of the Cretaceou 
epoch, I will give brief results of my investigations, reserving for future 
work more elaborate details. 
HETEROPOKA RETICULATA, Busk, ‘ Crag Polyzoa,’ p. 121. 
Ceriopora dichotoma (pars), Goldf. ‘ Petrif. Germ.’ pl. x. fig. Qe. 
Heteropora _,, Hagenow (Busk as above). 
