MADEIRAN GROUP. ]99 



manifestly mistaken ; for a single glance at the two species, 

 placed side by side, will shew an abundance of characters by 

 which they may be at once separated from each other, for, in 

 point of fact, this Canico shell is about midway between the 

 South-Desert an H. coronula and the (very dissimilar) H. tiar- 

 ella of Madeira proper. Yet, unless I am much mistaken, the 

 Baron Paiva (as mentioned in the preceding foot-note) had his 

 diagnosis of the South-Desertan shell drawn out (probably after 

 Mr. Lowe's report in 1862), with the addition of a 'var. a. 

 minor ' for a Madeiran. form of it (which was clearly intended, 

 although inaccurate as to its details, for this particular one from 

 the neighbourhood of Canico and Graula) ; but, finding after- 

 ivards that the latter was specifically distinct, he enunciated it 

 (in 1867) as the ' H. MonizianaJ unfortunately, however, 

 omitting (as it seems to me) to erase the ' var. a.' from the 

 other and previous description ! But that this ' var. a. minor ' 

 of his H. coronula is one and the same thing with his after- 

 defined H. Moniziana is I think well-nigh certain ; and indeed 

 his mere habitats would tend, even of themselves, to imply as 

 much, the former one being ' ad excelsos montes septentrio- 

 nales insulse Maderce, rarissima, ad herbarum radices fere 

 sepulta ; ' whilst the latter is * rara sub lapidum acervis, in solo 

 humido fere sepulta prope vicos insulae Maderce Cameo et 

 Gaula.' ! 



As just stated, the H. Moniziana is about midway between 

 the South-Desertan H. coronula and the Madeiran H. tiarella, 

 though at the same time perfectly distinct from both of them ; 

 in which respect it is analogous to the 6rrea-Desertan H. Grab- 

 hami, which is equally intermediate between those two species, 

 and yet altogether distinct from the Moniziana. In its com- 

 paratively wide and open umbilicus, as well as in the peculiar 

 character of its (nevertheless much more feebly indicated) basal 

 sculpture, it partakes of the former (i.e., of the coronula); 

 whilst in the shape and details of its upper portion (though the 

 spire is much less elevated, and the sculpture is much less coarse, 

 than that of the H. tiarella) it has more in common with the 

 latter. It is however a rather thinner shell than either of them ; 

 and its surface is of a uniform, dull, opake, griseous-white, 

 instead of being slightly variegated as in the H. tiarella. 



1 As though to make matters even still more complicated, the Baron Paiva, 

 after speaking of his H, Moniziana (which was found by the collector whom 

 he sent out to work for him), adds ' Primus anno 1864 inveni ; ' yet, by his 

 own acknowledgement on the preceding page, he had already transmitted it 

 to Mr. Lowe in 1862 ! So that I am compelled to arrive at the conclusion 

 that his statements, diagnoses, and habitats are so untrustworthy and confused 

 that little reliance can be placed upon them, and that we must consequently 

 proceed on independent evidence (which, fortunately, in this instance, 

 happens to be accessible). 



