THE NAUTILUS. 13 



brown, varying to whitish, with the surface dull, above and 

 below, minutely granular, not very conspicuously striate; 

 aperture round, the peristome continuous, livid brown. The 

 umbilicus is rounder than in dealbata; in the latter species it 

 is distinctly contracted, and therefore not round. In the dull 

 surface the shell resembles G. (Spirorbula) depauperata, but 

 it differs by the wider umbilical region, with much more of 

 the penultimate whorl showing. In the form of the umbilical 

 region it resembles G. (Disculella) fictilis Lwe., but it is con- 

 siderably larger than fictilis and lacks the glistening surface. 

 The animal is pellucid whitish. 



I found this abundantly on Cenouras Island, off the east 

 side of Porto Santo, January, 1921. The snails of this small 

 island have not previously been collected, so far as I can learn. 

 The island is barren, with a scanty vegetation consisting of 

 Microstigma maderensis (Matthiola maderensis Lowe), Lotus, 

 etc. I could not find any ants or millipedes. The same plants 

 and the same general conditions are found on the Ilheo de 

 Nordeste, a short distance away, yet the snail faunas of these 

 two islets are very different. Nordeste possesses a fine Lep- 

 taxis (forensis Woll.), and swarms with a Discula (gomesiana 

 Paiva). On Cenouras I found no Discula, except a single 

 dead and broken G. cheiranthicola- (Lowe), which, as Mr. A. 

 C. de Noronha suggests, may have been brought by a bird. 

 On Nordeste we found a small variety of G. (Caseolus) abjecta 

 (Lwe.) in some numbers, but the shells were all dead. 



The group Disculella contains rather discordant elements. 

 G. leptoticta (Lwe.) of Madeira, and the related G. microm- 

 phala (Lw 7 e.) of the Desertas stand apart, having a granu- 

 lated surface, small umbilicus, no keel, and peristome not 

 strictly continuous. They should, I think, be transferred to 

 Caseolus. G. spirulina n. n. (Helix spirorbis Lowe, 1852, not 

 Linne, 1758) is tfie smallest of the series, and G. campar 

 (Lwe.) is easily known by the elegant ribbing. 



I recently received G. micromphala from the Southern De- 

 serta (Bugio), collected by Mr. C. B. Cossart. According to 

 Paiva, spirulina and leptosticta also occur there, but several 

 of Paiva 's Bugio records are improbable and in need of con- 



