ON FOSSIL POLYZOA. 263 



Professor Braun says that it extends from the Lower Lias onward into 

 the White Jnra and also into the Great Oolite of Ranville. It is also 

 found about Metz. Through the kindness of Professor Roemer of Breslau 

 I have had supplied to me the species of Ceripora, Goldfuss, which are 

 referable to this genus, but the types diflfer in many particulars from our 

 own species. 



One peculiar type is separated from the genus Neuropora by Haime, 

 and is made the Oolitic type of the genus Acanthopora, D'Orb. It is 

 the Ghrysaora spinosa of Michelin. A specimen of the genus Semycitis — 

 another Ghrysaora type — was found by Walton at Bath. The British 

 species of Neuropora and allies are — 



Neuropora spmosa, Lamx. := Ghrysaora spinosa. 



„ dumicornis „ = „ dumicornis. 



and Geriopora angulosa, Quen. 



,, Befrancii, Haime. 



1834. Heteeopoea, Blainville. 



We have now left one group of Oolitic Fossils which within the last 

 few years have been more closely studied than any of the others, because 

 of their supposed relationship with the Palaeozoic Monticulipora. 



In his ' Petrifactions of Germany,' Goldfuss placed in the genus Oerio- 

 jpora three species, which he describes and figures ' as containing large and 

 small openings on the surface of the branches. These were Geriopora 

 anomalopora, C. cryptopora, and G. dichotoma, all of which were from the 

 Mastricht beds of Astrupp or Nantes. In 1834 M. de Blainville separated 

 these from the Geriopora of Goldfuss, and established another one for their 

 reception which he called Heteropora, assigning as essential structures the 

 two sorts of openings, but giving very few details respecting the genus. 

 After this Milne-Edvvai-ds added to them Millepora dumitosa and corigera, 

 Lamouronx. In his 'Miocene Fossils of North America,' ^ Mr. Lonsdale 

 oomplained of the inadequate description of Blainville as not having in 

 it sufficient details ' to enable an opinion to be formed of its complete 

 characters, or of the nature of the minor openings.' This error was to 

 some extent rectified by Lonsdale, and we owe to him the merit of being 

 the first author who clearly indicated upon sufficient grounds the real 

 zoological position of the genus. Jules Haime, in his ' Jurassic Bryozoa ' 

 (pp. 207-8), redescribes the genus, and as his diagnosis has particular 

 j?eference to Oolitic types, I reproduce a portion of his description. 



' Zoarium of variable form, but chiefly dendroid. 



' Zooecia apparently united by some lamellar prolongation of the walls, 

 whence result some intermediary tubes, the terminal aperture of which 

 has been closed by a thin calcai'eous pellicle, but which perhaps were 

 themselves intended to become young cells. When externally examined 

 two different sets of openings are seen, varying in size, sometimes circular, 

 at other times polygonal. . . . There are fundamental differences between 

 the peristomes of the true cells and those of the intermediary openings ; 

 still, the matter of the young cells is very uncertain, and is not of any 

 specific value (?).' 



In accordance with this decision, Haime admitted only two species — 

 Heterojiora conifera and H. pustulosa- — where Michelin admits seven, and 

 D'Orbigny eight. 



' Petrifactions, pi. x. fig. 1-5, fig. 3, fig. 9, &;c. 

 - Quart. Jour. Geo. Soc. vol. i. p. 500 (1845). 



