514 MAZATLAN UNIVALVES 



659. PlSANIA INSIGNIS, Rve. 



Buccinum. mutabile, (pars,) Val. Voy. Yen. Moll. pi. 6. 



f. 2, 2a-e, 1846; f. 2 <?,/., 2 a> 0, excl. (non Zmra.) 

 B. insignis, Rve. Condi. Ic. pi. 8, f. 58, Dec. 1846. 

 B. insigne, C. B. Ad. Pan. Shells, p. 69, no. 59. 

 (Cantharus) Tritonidia insignis, H. fy A. Ad. Gen. i. 85. 



If the name of Val. was published before that of Rve., the 

 law of priority would require that this species should be called 

 Pisania mutabilis ; but as it was given in ignorance of its 

 preoccupation in the original genus, and also to include both 

 this species and P. gemmata ; and as Reeve's name, given in the 

 same year, is much more widely diffused, it is here retained. 



This beautiful, but by no means typical species varies in the 

 height of spire, development of ribs, colour, and amount of 

 basal twist. The nuclear whirls are smooth ; those which 

 follow are swollen, with the radiating costse always well deve- 

 loped, and crossed by somewhat irregular spiral lirulae, of 

 which two are larger than the rest. On the ultimate whirls, 

 the costse are often nearly obsolete, and are never produced to 

 the base. Very fine lines are seen between the principal ones, 

 which are at irregular distances. Colour purple brown, more 

 or less spotted with white, especially at the tubercles of the 

 two principal lirulse ; mouth white, sometimes bordered with 

 dark. When young, the shell somewhat resembles Fasciolaria, 

 having a few very slanting columellar folds, without labium or 

 teeth. It is only when quite adult that the Pisanoid form is 

 developed. Canal rather long, bent ; labium rarely thickened 

 so as to shew an umbilical chink. Lab rum generally ribbed 

 within. Operculum resembling that of Turbinella, but thinner, 

 less twisted ; outside with irregular coarse strise of growth, 

 and a channel along the outer edge ; inside glossy, with a few 

 irregular lines on the muscular scar. Colour olivaceous, with 

 a yellowish tinge inside. The shell is rarely encrusted, even 

 \*ith Serpulse and Bryozoa. The largest of the specimens 

 measures long. 2 '08. long. spir. 1'13, lot. 1*1, div. 4D. 



A transverse sp. 1'44, '68, '94, 60. 



Hob. St. Elena ; in clefts of rocks at low water ; Cuming. 

 Panama ; not uncommon ; in the same situation, but more 

 frequently under stones, and especially under those which 

 were lying on sand ; C. B. Adams. Mazatlan ; very com- 

 mon ; L'pool fy Havre Coll. 



