229 



leamers, likę the author of the present paper, such ditferences are 

 exceedingly perplexing. 



115. MONOCEROS BREVIDENS, Cour. 



p. (Monoceros) brevidens, Conr. Joum. p. 264 : diagn. auct. 



"M. t. fusiformi, solida, spira curtiore ; anfr. superne angulo 

 haud saliente munitis," tumidioribus basin versus ; " acantha 

 curtiore, solidiore ; spiraliter sulcatis," suleis interdum obso- 

 letis. 



Monoceros unicarinatum, Sow. Conch. 111. no. 14. p. 4. f. 5 ; non 

 Reeve, Conch. Ic. sp. 1, nec Desh. iu Lam. An. s. Vert. no. 10, diagn. 



= Monoceros, pi, 1. f. 2 (non sp. 2) ; Reeve, loc. cit. 



Non Monoceros brevidentatvm, Gray in Wood, Suppl. (1828) 

 p. 12. no. 10, p. 43. pi. 4. no. 10 ; Sow. Conch. 111. f. 4 ; Reeve, 

 Conch. Ic. pi. 1. sp. A. L A a, b; Desh. in Lam. An. s. Vert. vcl. x. 

 p. 123. no. 9=Purpura cornigera, Blainv. Nonv. Ann. Mus. vol. i. 

 p. 213. no. 28. pi. 9. f. 10 ; Kien. Icon. Conch. p. 123. no. 78. pi. 39. 

 f. 92=Monoceros maculatum, Gray ipse m Zool. Beech. Voy. p. 125. 



Hab. Sta. Barbara. Mus. Nutt., Cum., Jay. 



The exact date of Sowerby's species, which is generally referred to 

 the P. engonata of Courad, but differs from the figure of that shell, 

 and agrees much better with the description of this, is difficult to 

 determine. The volume bears date 1841. lt differs frora P. engo- 

 nata in being swollen at the base, with less sculpture and apgulation. 



116. Monoceros lapilloides, Nutt. 



P. {Monoceros) lapilloides, Conr. Joum. p. 285. pi. 20. f. 18 

 (1837). 



"M. t. fusiformi, curta, solida; anfr. superne vix concavis ; suleis 

 spiralibus obsoletis; pallida, maculis fuscis quadratis seriebus 

 spiralihus ornata ; apertura et columella purpureis ; labro mar- 

 ginėm versus albida." 



= Monoceros punctulatum, Sow. Conch. 111. p. 4. no. 13. f. 3. 



= Monoceros punctatum, Gray in Zool. Beech. Voy. (1839), p. 124; 

 Reeve, Conch. Ic. sp. 2. pi. 1. f. 1 (non f. 2). 



Hab. Sta. Barbara (Nuttall). Is. Cocos, in rupibus (Capt. Col- 

 nett). Mus, Brit., Nutt., Cuming, &c. 



The differences betvreen the specimens of Californian Monoceros 

 are so numerous, and similar species from other ąuarters are so vari- 

 able, that the three species here repeated from Conrad are given with 

 very great hesitation. That the forms figured by Sowerby and Reeve 

 are conspecific, is by no means improbable ; the form engonata is 

 the most aberrant, but it is by no means unapproached. 



MuREx, Subgenus Cerostoma, Conr. 

 Murex ; labro ut in Monoceros (Acanthina) dentato, dente erecto. 



117. Cerostoma Nuttalli, Conr. Joui-n, p. 264. pi. 20. f. 22 ; 

 Jay's Cat. no. 8298. 



Hab. Sta. Barbara. Mus. Nuttall, Jay. 



