1873.] MR. R. B.WATSON ON MADEIRAN MOLLTJSKS. 365 



across the body ; in front it is crossed obliquely by a shallow open 

 depression. 



Sh. M. 8. 7. 6. 5. 4. 3. 2. 1. 



L...-159 -063 -069 -027 "023 -014 -01 -007 "004 -003 

 B. ..077 -049 -059 -066 -054 '039 -026 -019 '013 -006 



Hah. Selvagens, shore. 



By the specific name I have selected for it, I desire to acknow- 

 ledge my obligations to the Baron do Castello de Paiva, to whom I 

 owe it and all the other shells I possess from the Selvagens. They 

 were procured by him from the men who annually visit these some- 

 what inaccessible islands for barrilha, orzella, and sea-birds. The 

 Rev. R. T. Lowe has given a very interesting notice of the flora of 

 the Selvagens in a little work published three years ago by Van 

 Voorst ; I regret that I can communicate so very little regarding 

 their Mollusca. I may take the opportunity, however, of stating 

 the fact, which has not, I think, been published as yet, that Helix 

 coronula, Lowe, has been found (it has been communicated to 

 me by the Baron de Paiva) in these islands, where previously the 

 only land- shell known to exist was H. ustulata, Lowe, a species 

 found nowhere else in the world ; H. coronula has also been found 

 by the Baron's collectors in Bugio (the Southern Deserta) and at 

 Cameo, one of the nearest points in Madeira, — facts of great interest 

 in connexion with the distribution of species, and serving to connect 

 through their fauna Madeira and these little islands, which, as 

 regards their flora, are, according to Mr. Lowe, more nearly related 

 to the geographically more contiguous Canaries. 



~CJ fbh R ISSOA leacocki, Watson. (Plate XXXIV. fig. 1.) 



Shell conic-oblong, solid, squarely tubercled, transparent, glossy. 

 The two lines of the spire, from the periphery to the apex on the 

 left side of shell, and from apex to extreme corner of mouth on 

 the right, are perfectly straight, broken only by the square ditch-like 

 sutures, while the basal line connecting these two is an unbroken 

 curve ; this arises from the fulness of the base and the thickness of 

 the pillar. 



Sculpture, longitudinal threads, 15 to 18, strong, oblique, trace- 

 able from whorl to whorl, disappearing on If whorl, running down 

 almost to the very point of base ; the last appears as a strong broad 

 white labial rib. Spiral threads of about the same size cross these 

 longitudinal threads, forming large knobs or tubercles at the inter- 

 sections ; these knobs are less strong on lower part of base, but are 

 often traceable even on the spiral threads of the pillar, where they 

 form the only representatives of the longitudinal threads, which die 

 out in the interstices of the spiral threads on the base. Of these spiral 

 threads there are eight or nine on the last whorl. Two additional 

 but feebler ones generally appear between the three highest just 

 before they reach the labial varix, which they all strongly cross, but 

 stop short of the extreme edge of the mouth, leaving in advance of 

 them a plain narrow margin ; on the fourth and fifth whorls there 



