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BRITISH DEVONIAN BRACHIOPODA. 



Even a few of the 65 above enumerated may still require further consideration ; for 

 instance, under Spirifera curvata (of which Schlotheim's typical shape occurs at Hope's 

 Nose, near Torquay) have been included some decorticated specimens, bearing much 

 resemblance to Sp. glabra, but which we have provisionally left with Sp. curvata, on 

 account of the transverse lines characteristic of that species, which are also observable on 

 some " glabra" -like specimens of Sp. curvata. The same observation may be made with 

 reference to certain variations in shape of Sp. undifera, which, when deprived of their 

 transverse lines or sculpture (from the effects of fossilisation), it is quite impossible to 

 distinguish from the Carboniferous Sp. ovalis. The material at hand in connection with 

 Mhynchonella Pengettiana, the largest British Devonian species of the genus with which we 

 are at present acquainted, lias not been sufficiently complete to enable us to give a perfect 

 representation or description of the shell. Mhynchonella laticosia is also a good and 

 common form in certain Upper Devonian localities ; but, as is the case with P. Pen- 

 gettiana, it occurs only in the shape of distorted and compressed casts, so that it is almost 

 impossible from such material to describe the exact form of the shell. It will also have 

 to be determined, by further examination, whether Ph. angulata is a distinct species from 

 Pli. primipilaris, and its variety implexa, as well as whether Ph. (?) Ogwellicnsis, Ph. (?) 

 protracta, and Ph. (?) Lummatoniensis, really belong to the genus Phyncltondla, or if one 

 or more of them might not be referable to Camarqphoria. Some uncertainty may also 

 prevail with reference to the question which relates to Streptorhynchus umbraculum and 

 St. crenistria, which some palaeontologists have considered to be distinct species, but which 

 others have combined in one. More material and examination of Strept. gigas will also be 

 desirable, the distorted specimens from Cornwall at command not being sufficient to 

 enable us to make out all its characters. The genera, or sub-genera, to which Zeptana? 

 nobilis and Z. (vel Or this) laticosta should be referred, has still to be accurately deter- 

 mined. Some doubt has also been expressed with reference to OrtJiis striatula and 0. 

 resupinata being distinct species ; and it must be allowed that, if distinct, the difference is 

 but small. It is likewise probable that Chonetes sordida and Ch. Hardrensis belong to 

 the same species, — this point will, however, require further consideration, as the material 

 from Linton, with reference to Ch. sordida, was very imperfect. We will now enumerate 

 those forms of which the greater number, if not quite all, may prove, when better known, 

 to be good species, but of which the material hitherto procured from our British 

 Devonian rocks has not been sufficient to enable us to arrive at a satisfactory 

 identification. 



