374 BULLETIN OF THE 



These species are somewhat puzzling. With the external sculpture and um- 

 bilicus of a rather conical Solariella, we find in adult specimens a well marked 

 blunt tooth on the columella, and the aperture opposite furnished with raised 

 lira?. In other specimens these are not visible, but then it is impossible to 

 say that they are completely adult. The sculpture runs the usual gamut of 

 evenly reticulate; nodose reticulate, the intersections marked by little imbri- 

 cations while most of the network is obsolete; and, finally, of uneven reticula- 

 tion where the cords one way are much stronger than those by which they are 

 intersected. None of the specimens contained the soft parts, so their relations 

 must for the present remain problematical. The group is hardly Thalotia, 

 being umbilicate; it is certainly not a Euchelus or Craspedotus. Perhaps the 

 most reasonable conclusion, in the absence of more information, is that this sec- 

 tion bears to Thalotia about such a relation as Eutrochus bears to Calliostoma. 

 The tooth is on the pillar, not at its anterior end. 



Genus MARGARITA Leach. 



Margarita Leach, Journ. de Phys., LXXX VIII. p. 464, 1819, Appendix to Ross's 



First Voyage, 1819. 

 Margarita Broderip & Sowerby, Zobl. Journ., IV. p. 363, 1828. 

 Margarites Leach MS., 1819, Gray, Ann. Mag. Nat. Hist., XX. p. 268, 1847; Synop. 



Moll. Gr. Brit., p. 197, Dec, 1852. (Type, M. hehcina Fabr.) 

 Eumargarita Fischer, Man. Conch., p. 825, 1885. 

 Not Margarita Leach, Zool. Misc., I. p. 107, 1814, = Margaritifera Da Costa (1776) 



et al. ; Unionum Link (1807); Margaritijihora Megerle (1811); Meleagrina 



Lamarck (1812); etc. 



In 1814 Leach used the name Margarita for a section of Avicula, which had 

 already received several names. The name Margarita was therefore a synonym. 

 In 1819 he used the same name, this time for a valid genus; but, apparently 

 recognizing that this might cause confusion, he changed its termination in a 

 work which he had in press in 1820, and which was interrupted by his death. 

 This work was published some thirty years later by Dr. J. E. Gray. 



The second .use of a generic name once fallen into synonymy, although 

 not forbidden by the accepted rules for nomenclature, is greatly to be depre- 

 cated; yet when it has occurred, and when the second application of the name 

 is universally unchallenged for more than half a centur\ r , and the original 

 application never was in use and has been absolutely ignored, I can see no 

 benefit likely to accrue to science from a change of names. It cannot be too 

 clearly understood that an ex post facto application of rules, however useful in 

 themselves and for present guidance, to - the work of authors preceding La- 

 marck's Animaux sans Vertebres, will produce nothing less than confusion and 

 annoyance. We have a right to insist on a consistently binomial nomenclature 

 and strict priority for all names, but to attempt more is to invite chaos to come 



