PATELLA. 431 
Aatella fissura, 
The brief description of this shell would apply to almost 
any Hmargimula the synonymy to the HE. reticulata of our own 
coast exclusively, and, as the features of that limpet (the Patella 
Jissura of the earlier British writers) are not opposed to the 
stated characteristics, the species may be regarded as pictorially 
defined. It is probable enough, as Récluz has remarked, that 
the Algerine specimens belonged to the E. cancellata of Philippi, 
of which an example (Moll. Sicil. pl. 7, f. 15) is present in the 
Linnean cabinet; it is not, however, abundant at Algiers, for I 
did not procure one individual during my sojourn in Barbary. 
The expressions “‘ vertice reflexo” and “ fissura linearis a latere 
antico ad lateris medium” are, indeed, peculiarly appropriate 
for that beautiful shell (said to be the EH. fissuwra of Lamarck’s 
cabinet), yet as the slit, properly speaking, does not extend to the 
middle in mature examples of either limpet, and the reflection of 
the summit is apparent in all but the more aged forms of reti- 
culata, there is no necessity for depriving our British shell of that 
appellation to which it was entitled by the published synonymy. 
As the name, however, alludes to a character common to every 
member of the genus, it is now generally disused ; consequently, 
in referring to the Patella fissura of Linneus, one may dis- 
tinguish the two confused species as “var. Brit.” and “ var. 
Alg.” 
Aatella pustula. 
It is usual to identify this key-hole limpet with the Fissurella 
pustula of Lamarck (List. Conch. pl. 528, f. 3), which, indeed, is 
present in the Linnean collection, but is neither marked as such 
nor accords with the described features. ‘The addition to the 
synonymy, in the twelfth edition of the ‘Systema,’ of Petiver’s 
representation of that shell, was doubtless the source of the 
mistake ; for mistake it certainly must be to recognise a rose- 
tipped species, with only obsoletely crenated radiating costelle, 
