MUSEUM OF COMPARATIVE ZOOLOGY. 75 



About 1819 the young shell of Fissurella r/rceca, -which had been described as 

 a separate species {Patella Jissura) by Montague, attracted the attention of 

 Messrs. Brown, Leach, and Gray, on account of the spiral apex, which disap- 

 pears in the adult, a fact not recognized by them. Brown claims to have first 

 pointed this out to Leach, and to have proposed to call the shell by the new 

 generic name of Sipho, which he published in the latter part of 1827 in his 

 Illustrated Conchology of Great Britain. He complains that his name was not 

 adopted, and that Dr. Leach preferred to name the shell Cemoria. Meanwhile 

 it would appear that Dr. Leach's intimate friend and pupil, Mr. J. E. Gray, was 

 unaware of the proposed name of Dr. Leach, since in 1821, without a descrip- 

 tion, he suggested for the shell in question the name of Dlodora. Blainville 

 erroneously supposed Gray's sole species to be Patella noadiina of Linnaeus, 

 and so refers to it in a note without adopting or describing it. To his original 

 Cemoria Dr. Leach afterward added a shell, which he received from Fleming, 

 under the name of C. flemwgianus as a second species, but of neither was any 

 publication made. In 1827 Lowe properly defined and published his genus 

 Puncturella, stating that he believed it to have formed one of Leach's unpub- 

 lished species of Cemoria. The name Cemoria was used by several authors 

 without any description subsequent to Lowe's publication, but was only pub- 

 lished by Dr. Gray from the manuscripts and unpublished plates of Leach, in 

 December, 1852. If unpublished and undescribed names are to have any 

 place in nomenclature the name Diadora from Blainville's erroneous reference 

 has the first claim. But since this is properly forbidden by the rules of no- 

 menclature, the only name having any just claim to priority is that of Lowe, 

 which has accordingly been adopted by the best authorities. Believing that 

 the introduction of unpublished names leads only into the limbo of inextricable 

 confusion, I have no hesitation in following the example of the eminent au- 

 thors of the British Mollusca, and adopting the name Puncturella. 



Puncturella circularis n. s. 



Shell white, acutely conical, with the anterior wall slightly, and the poste- 

 rior wall strongly concave ; tip sharply recurved, acute, not spiral, directed 

 backward in the middle line ; surface ornamented with about forty very slen- 

 der radiating lines, fewer toward the apex with intercalary threads toward the 

 margin ; concentric sculpture consisting of extremely delicate, irregularly dis- 

 posed aggregations of the lines of growth, which now rise above and now fall 

 below the general plane of the surface, giving it under a strong magnifier a 

 curiously malleated appearance, between the radiating threads, nowhere exhib- 

 iting any uniform concentricity ; where the lines of growth cross the radiating 

 threads they form fine overlapping scales closely appressed to the threads ; 

 puncture ovate, pointed behind ; margin thickened, perfectly smooth ; septum 

 triangular, inclined forward under the puncture which it almost entirely hides 

 when viewed from below ; basal edge subcircular. Lon. 5.75 ; lat. 5.0 ; alt. 

 3.0 mm. 



