ANIxVLALS. Ill 



a step which I consider one of the most important that has of late been made in 

 malacological classification. 



I propose placing in this family the genera Isorkynchus, Hypothyris, Camarophoria, 

 Uncites, and Pentamerus ; but looking at such forms as Hypothyris psittacea,^ Chemnitz, 

 H. excavata, Phillips, H. concinna, J. Sowerby, H. Wilsoni, J. Sowerby, H. acuminata, 

 Martin, H. pUcatella, Dalman, and some others, which are for the present included in 

 the same genus, it would appear to consist of more genera than those above named. 

 M. Alcide d'Orbigny has indicated or described some, which may be admissible ; but 

 not being sufficiently acquainted with their characters, I can only make this passing 

 allusion to them. 



The genus Hypothyris was first proposed provisionally by Professor Phillips in 1842, 

 for shells having the " beak acute, the perforation below it,"^ and which had been 

 previously distinguished (though not named) from the apically-foraminated Terebratulas 

 by J. Sowerby, Von Buch, and Eudes-Deslongchamps. The group to which the name 

 was applied is sufficiently obvious ; it is to be regretted, however, that Professor 

 Phillips did not point out its type — a circumstance which induced me, when endeavouring 

 to establish the group as a genus,* to, make free in typifying it with the Atrypa cuhoides' 

 of J. de C. Sowerby.® 



1 M. A. d'Orbigny has made this species typical of his geuus Hemithyris ; but in what respect does it 

 differ from the true Hypothyrises ? 



^ Palaeozoic Fossils, &c., p. 35. 



^ I was not aware, until my friend Mr. T. Davidson called my attention to the fact, that M. Eudes- 

 Deslongchamps had published his remarkably correct (that is, for the period, 1837) 'Tableau Synoptique 

 d'un Arrangement systematique des Brachiopodes fossiles des Terrains du Calvados ;' otherwise it would 

 not have been overlooked in my paper on the ' Palliobranchiata.' I perceive some of the divisions of this 

 Tableau are equivalent with certain of the new genera I have proposed. 



* Vide Annals and Magazine of Natural History, vol. xviii, p. 28. 



5 I was prevented placing the first species {Terebratula proboscidialis, Phill.) which Professor Phillips 

 described under the head of the group, as the type of Hypothyris, from being uncertain as to whether or not 

 it belonged to the genus. 



^ I feel it necessary to make a few remarks in this place on the name which is here applied to the present 

 genus. Fischer de Waldheim in his 'Notice sur les Fossiles du Gouvernement de Moscow et sur les 

 Coquilles fossiles dites Terebratules,' published in 1809, was the first to separate the plicated or sub- 

 apically foratninated Terebratulas from those with an apical foramen, under the two divisions Trigor<^lla 

 and Rhynconella, each apparently respectively corresponding with the groups Pugnacee and ConcinncB of 

 Von Buch ; but they are so imperfectly characterised (a fault common to that period), and the type of each 

 is so difficult to identify with any known species, that it must be evident to every one, these divisions, 

 before they can be adopted, require to be entirely rearranged. Reverting for a moment to the types named 

 by the celebrated Oryctographer of Moscow, I would ask, is anything satisfactorily known respecting the 

 Trigonella atoma, and Rhynconella loxia? Has anyone been able to identify these shells? What formation 

 do they belong to ? and where are their localities ? The foregoing remarks have suggested themselves in con- 

 sequence of some authors regarding Fischer de Waldheim' s Rhynconella, as rearranged by M. A. d'Orbigny, 

 to be the same as Hypothyris : this may, or may not be the case : — for my part I am not able to give an 

 opinion on the matter, being quite unacquainted with what species the learned author of the ' Palaeontologie 



