i>:;s TESTACEA ATLANTICA. 



Genus 11. CLAUSILIA, Drap. 



Clausilia crispa. 



Helix crispa, Lowe, Cambr. Phil. S. Trans, iv. 65. t. 6. f. 36 

 (1831) 



Clausilia crispa, JPfeiff., Mon. Hel. ii. 484 (1848) 



„ „ Lowe, Proc. Zool. Soc. Loud. 215 (1854) 



„ „ Alb., Mai. Mad. 70. t. 16. f. 17-19 (1854) 



„ „ Paiva, Mon. Moll. Mad. 142 (1867) 



Habitat Maderam sylvaticam ; in intermecliis, praecipue ad 

 truncos et sub cortice laurorum arido laxo, degens. In statu 

 semifossili, ad Canical, parce occurrit, — ibidem varietatern 

 niajorem (= var. decolorata, mihi), sed paulo grossius costulata, 

 simulans. 



The large and beautiful Clausilia crispa (so remarkable, 

 inter alia, for the fine costse of its entire surface being densely 

 crowded together, and on the basal volutions very minutely un- 

 dulating) is confined to Madeira proper, where it occurs princi- 

 pally beneath the loosened bark of old laurels within the damp 

 sylvan districts of intermediate altitudes ; and it is surprising 

 to me that Mr. Lowe, in spite of his almost unparalleled accu- 

 racy, should have failed to record (even whilst possessing an 

 abundance of material from which to judge) that it puts on two 

 very opposite phases, which might well nigh have been treated 

 as specifically distinct did they not merge into each other by 

 intermediate gradations. The form which he described under 

 the name of C. crispa (and which must therefore be accepted 

 as the typical one) is the smaller of them, and is of a more or 

 less dark brown but elegantly marbled with irregular yellowish- 

 white cloudy dashes and smaller longitudinal streaks (the latter 

 of which are many of them subconfluent) ; whilst the other 

 (which I would define as the ' var. /3. decolorata ') is consider- 

 ably larger, of a more or less pale yellowish-brown, or browuish- 

 white (and therefore concolorous, or free from pallid blotches 

 and streaks), and with the peristome not only a little more 

 deltoid in outline, but likewise broader and more outwardly 

 flattened or developed. This latter state, which I have met 

 with commonly on the trunks of old laurels at S. Antonio da 

 Serra, as well as in the Eibeira de Sta. Luzia and elsewhere, I 

 would enunciate briefly as follows : — 



Clausilia crispa, var. /3. decolorata. — Major, plus minus 

 obscure fulvescenti-albida, concolor (nee marmorata), costulis 

 undique paululum magis elevatis, apertura vix magis deltiformi, 

 peristomate latiore aut magis expanse — Long. 6-8 tin. ; diarn. 

 maj. 2. 



