314 



irregularibus spiralibus haud extantibus, et rugulis incrementi 

 ornata ; intus, anfr. primis et ultimis quoad iv. apertis ; 

 mediis laminatis ; lafnina svperiore muito majore, prius con- 

 spicua, a columella extunte ; prinmm simplici ; dein angulo 

 recto rejlexa, extus carinis i. -iii. guarmn ii. acutissimcB ; la- 

 mina inferiore simplici, a columella extante, alterre juxta 

 carinam f ere attingente ; lamina tertia minima, intercalante, 

 inferiori pcBne attingente ; laminis tetiuissimis, albis, diaphanis, 

 lineis incremetiti conspicuis ; pagina interna maxime nitente, 

 transversim haud septato. 

 Diam. spirse •23, aperturse '07. 

 Hab. Mazatlan ; haud rare Uvanillis, Curais, Muricibus, &c., 



adhserentes ; Reigen. Panama. Mus. Cuming. 



In this little species, the structure is the most delicate and com- 



plex of any of the species examined. For particulars v. B. M. Cat. 



2. Petaloconchus cochlidium, n. s. (fig. 2.) 



P. t. irregulariter spirali, glomerata, anfr. pluri7nis confertis ; 

 spirce marginibus f ere parallelis ; dense rubro-fusca ; rugis 

 spiralibus iii. in basi aliis, interstitiis cancellatis, profunde in- 

 terpunctatis ; sculptura scepe obsoleta ; intus, laminis duabus 

 ab axi procedentibus, tenuissimis ; superiore majore, ad angu- 

 lam obtusam curvata, carinis duabus validis labrum versus in- 

 strueta ; inferiore tninore, alteram versus procedente, interstitio 

 satis magno ; lamina tertia parva intus super inferioreni šita. 

 Diam. spirse "2, aperturse "08 poli. 

 Hab. Australia. Mus. Cuming. 



This species is known from P. macrophragma by the upper 

 lamina being bent at a more obtuse angle, and by the third lamina 

 being proportionally large, growing out of the second. The shell is 

 of a lighter colour, and of larger growth. Occasionally other small 

 keels and plaits are seen. In one specimen (near the attachment of 

 the locality ticket) occurs the extremely unusual appearance of a 

 septum traversing the laminse. Sometimes there is a falše appear- 

 ance of septa in shells of this genus, from other Vermetidce growing 

 in the šame group, or from adveutitious matter. 



3. Petaloconchus flayescens, ? n. s. (fig. 3.) 



P. t. irregulariter spirali, glomerata, parva ; anfractibus maxime 

 confertis, marginibus spirce s^ibparallelis ; rubido-favescente ; 

 rugis sjnralibus iii. -iv. validis, transversis minoribus, confertis, 

 interstitiis parurn punctatis ; sculptura interdum obsoleta ; 

 intus per maximam partem laminata, laminis duabus ab axi 

 procedentibus, tenuissimis; superiore majore, f ornicata ; infe- 

 riore recta, interstitio magno ; per atfractus paucos lamina 

 superiore bicarinata, per anfr. pauciores lam. inferiore bifur- 

 cata, laminulis subparallelis. 



Diam. spirae '14, aperturse 06 poli. 



Hab. Sicilia. Mus. Cuming. 



This shell may have been already describedby Phil. as a Vermetus, 



