422 TESTACEA ATLANTIC A. 



opake) surface, and its usually pale yellowish-brown hue, — there 

 being seldom (if ever) any indications of lighter dashes or streaks. 

 Its peristome (which is white) is rather broadly developed, and 

 the columellary margin is almost in a continuous curve with the 

 outside of the penultimate whorl (when backwardly produced). 1 

 Judging from one of his original types which is now in the 

 British Museum, d'Orbigny's B. Webbii (enunciated in 1839) is 

 nothing more than the myosotis, W. et B., in its perfectly nor- 

 mal state ; and Pfeiffer also rightly defined it (twenty years 

 later) as a Bidimus, — having drawn out his diagnosis from this 

 very individual. Yet it is singular that the latter should not at 

 once have perceived that it differs in no respect from a typical 

 B. myosotis which is placed almost alongside it in the same col- 

 lection. This exactly quadrates with the habitat which is given 

 for it (on the authority of Webb and Berthelot) by d'Orbigny, 

 namely ' Grand Canary,' — which is the particular island to which 

 the B. myosotis (which however is scarcely more, I think, than 

 a mere aspect of the variatus, W. et B.) is peculiar. Yet 

 Mousson has fallen into the error of regarding it as a ' Cionella ' 

 (or Lovea), from which it clearly is altogether distinct. But 

 that d'Orbigny, v who had the types of Webb under his immediate 

 eye, should have failed to identify it with the B. myosotis is 

 truly astonishing, — for if this type to which I have just called 

 attention is to be trusted, it does not represent so much as even 

 a ' variety ' (unless indeed it be just appreciably more shining) 

 of that common Grand-Canarian shell. 



Bulimus encaustus. 



T. B. variati statum normalem simulans, sed sensim major, 

 subsolidior, ac magis nitida ; anfractibus distinctius 7 (nee dis- 

 tincte 6, indistincte 7), sensim (ut in B. myosotis) longioribus, 

 subgrossius sed etiam magis irregulariter costulato-striatis, striis 

 perpaucis hinc inde altioribus necnon interstitiis saepe sensim 

 eubexcavatis ; apertura paululum majore, longiore, peristomate 

 (albo) subevidentius calloso-incrassato, margine columullari sub- 



1 The occasional obsolete indications of minute and fragmentary spiral 

 strife, which are just traceable on different parts of its surface, and which 

 are alluded to in the published diagnoses of this and some of the cognate 

 Bulinri, are no differential character at all, — for they are equally to be 

 observed, at times, in every one of the species. Neither is the exact number 

 of the whorls ; for although sometimes only six or seven are conspicuous, the 

 eighth (which is at others fully developed) may generally be seen, more or 

 less immersed, at the extreme apex. Nor indeed is the presence of a minute 

 corneous nodule (more or less expressed) near to the insertion of the right- 

 hand margin of the peristome ; for that little callosity is as often absent as 

 present in most of the forms, or species, and can scarcely claim therefore to 

 be distinctive of any one of them in particular. 



