S84 SPECIES OF THE SYSTEMA. 
searched for examples of it in the Linnean cabinet. One shell 
alone in the entire collection, a colourless variety of the Buli- 
mus detritus of authors (C. Pfeiffer, Deutsch Land and Siissw. 
Moll. pt. 1, pl. 8, f. 6), both fulfilled the requirements of the 
diagnosis and likewise agreed with the relative dimensions 
attributed to the two forms; and as the presence of H. pupa in 
the Linnean cabinet has been expressly recorded, I feel no 
hesitation in regarding that individual as the original type of 
our author. 
Helix Barbara. 
From a brief description, unaccompanied by the citation of 
any suggestive delineation, it has hitherto been impossible to 
determine this species with convincing certainty. Gmelin, 
whilst slightly altering, has added nothing to, the language of 
the ‘Systema ;’ Schréter evidently did not recognise it; Miiller 
entirely omitted it. Férussac placed it as an uncertain species 
between Bulimus calcareus and Bulimus acutus; Beck as between 
B. ventricosus and acutus; Dillwyn as B. acutus itself. ‘This 
last supposition is confirmed by a rigid analysis of the contents 
of the Linnean cabinet, wherein it is the sole species (and our 
author has recorded his possession of examples) which agrees 
with the diagnosis of the H. Barbara. ‘There are many speci- 
mens present; some of the ordinary form represented by Dra- 
parnaud; others, and these alone accord with the “ rudi,— 
fascia grisea cincta” of the description, coincide more aptly 
with the figure (24 of plate 3) in Gras’s ‘ Mollusques de France.’ 
The myriads of individuals of this species which swarm upon 
every bank and wall around Algiers might well cause it to be 
noticed by the correspondent of our author, the Swedish Consul 
(Brander) in that city. 
Helix amarula. 
I find nothing in the collection of our author which at all 
agrees with his account of this species. The two cited figures 
