304 MAZATLAN UNIVALVES 



354. VEBMETUS EBUKNEUS, Eve. 



V. t. alba, sen rubro-fusco tinctd, satis magnd ; anfr. spirali- 

 bus albis x.-xiv. ; primis iii. vctlde rotundatis, l&vibus ; dein 

 carind und acutd, dein duabus, postea tribus monstrantibus, 

 quarum una circa peripheriam major ; postea subito irregulari, 

 anfr. separatis, vix spiralibus, marginibus plerumque valde 

 divergentibus, parum seu ad sese, seu ad concham alienam 

 affixis $ spiraliter tenue et confertim striatd, costis interdwn 

 xubobsoletis ; adultd inter dum rufo-fusco tinctd. 



Operculo extus concavo ; foliis plurimis tenuibus alter d intus 

 alteram sitd ; radiatim tenuissime striulato, slriularum inter- 

 stitiis punctulatis ; intus marginem versus convexo, opaciore, 

 margine tenuissimo ; cicatrice circulars, trienti latitudinis haud 

 cequante, lirulis circiter xii. concentricis ornato. 

 Proc. Zool. Soc. 1842, p. 197: Condi. Syst. vol. ii. p. 46, 



pi. 152, f. 2. 



Comp. Vermetus pellucidus, Brod. fy Sow. Zool. Journ. vol. iv. 



1829, p. 369. " F. t.pellucidd, longitudinaliter striatd, apicem 



versus carinatd." (This description will suit the young of 



Y. eburneus, but is not sufficiently explicit for certainty.) 



The operculum is described from specimens in Mr. Cuming's 



collection, which are believed to be authentic, as they agree 



with that of V. Hinclsii in the B. M,, though differing essentially 



from the figure professing to be of that species in H. fy A. Ad. 



Gen. pi. 38, f. 8, a, b. An operculum agreeing even in the 



peculiar microscopic markings is seen in Mus. Cum. in a very 



different shell, which has lost its apex, but is probably an 



Aletes, and s not unlike A. squamigerus. The V. Hindsii 



seems to diffeir from V. eburneus in the arrangement of the 



keels on the turritelloid portion. 



About 30 young specimens of this very beautiful species 

 were obtained on Chamse and Spondyli ; but only two were 

 found adult, loosely entwined on a Chama. These, having 

 passed through the acid process, have lost their sculpture and 

 would hardly be known from A . centiquadrus, (with which 

 the later whirls agree in colour,) but for the Turritelloid 

 apices, which have fortunately survived. The sudden contrast 

 between the elegantly chiseled, alabastrine Pseudo-Turritella, 

 and the irregular, almost smooth subsequent whirls, is very 

 remarkable. A fossil species found by Mr, Kuttall at New- 

 bum, IS". Carolina, differs essentially from the Atlantic species, 

 and offers no marks by which it has been distinguished from this. 



