GASTROCH^NA. 



Spengieri Nova Acta Danica^ II. 

 ■ 



TESTA tubicola, bivalvis, sequivalvis, inaequi- 

 latera, siibcuneiformis, anticehiantissima hiatu; 

 ovali, posticfe attenuato. Cardo linearis, mar- 

 ginalis, subedentiilus. Vagina tubulosa, testa- 

 cea, antice attenuata, aperta, apertura biloba; 

 postice in clavam o vat am, clans am, terminata. 



The Genera Pholas, My a, Mytilus and Cham a, have by 

 turns served as the receptacle of the shells composing this 

 very distinct and highly interesting Genus ; our acknow- 

 ledgements are justly due to Spengler^ for having sepa- 

 rated it from all of them, and for distinguishing it as a 

 Genus. Lamarck has adopted Spengler's name, but he 

 has placed it next to Pholas, apparently not having known 

 that the animal forms its own testaceous tube, either as a 

 lining to the hollow it has previously perforated, or as a 

 covering for its shell in those instances in which it has not 

 perforated at all, but in which it has taken up its abode, 

 as it frequently does, within some spiral univalve : the 

 fact of the shell being enclosed in a testaceous tube of its 

 own depositing, renders it proper to remove it into 

 Lamarck's family of Tuhicolce, to which, indeed, it appears 

 to us to be more nearly related, though we remark a very 

 considerable analogy between the shelly tube of Lamarck's 

 Tubicola?, and the coriaceous epidermis which not only in 

 a great measure covers the shell, but also encloses the 

 tubes of the animal of his Pholadarice, and, consequently^ 

 think the two families might very properly be united. 



The GastrochsBna is an equivalve, inequilateral, 

 rather cuneiform bivalve, being rounded at the anterior 



