80^ 



Semilituus. Nautilus aemilituus. Lin. 7'rans. viii. p. Us. 



p. 196. 



Tab. 19. f. 3. B}' the afliftance of the Boyfian cabinet we find this is not 

 the Nautilus fub.irciiatidus of Adams, and conlequently not 

 figure 73 of Walker, as we had formerly been induced to 

 believe ; but is perle6lly difliniSl, and not before defcribed as 

 an Enolilli flielL We besr therefore the reference to thofe 

 author.s may be erafcd, as we have transferred them to 

 J^autilus fuharcuaiidus. Nothing however has occurred to 

 induce us to alter our opinion with refpe6l to this being the 

 fimilituus, originally figured by Plancus, Tab. 1 , fig. X. O. 

 and X. P. It is true the fpecimen from which our figure 

 was taken has no vifible curved volution at the end, but in 

 fome this part is lefs obfcure ; and in a drawing of a fpe- 

 cimen in the pofiefiion of Mr. Henry Boys, we perceive a 

 very diftin6l convoluted termination at the poflerior end. 

 Shells that are fubjedl to fuch material variation are difficult 

 to identify, and confequently error in fynonyms is fometimes 

 unavoidable ; this however is more excufable than multi- 

 plying fpecies beyond their natural limits^ 



SuBARCUATULus. Adams Microsc. p. 642. t. 14. f. 38. 



Tab. 19. f.l Turt. Lin. iv. p. 307. 



IFalker Min. Shells, f. 73. 

 Nautilus crepidula. Fiditel. t. I9. g. h. i. 



Shell fub-arcuated, fub-convoluted, femi-pellucid, glofly, 

 white, with the anterior or ftraight part containing about four 

 of the cells ; the poflerior half convoluted : vifible conca- 



merations 



