MADEIRAN GROUP. 271 



Auricula vespertina, 31orel., Hist. Nat. des Agor. 210. t. 5. 

 f. 9 (1860) 

 „ „ Drouet, Faun. Agor. 169 (1861) 



Alexia Loweana, Pfeif., Mai. Bldtt. xiii. 145 (1866) 

 „ „ Paiva, Moil. Moll. Mad. 154 (1867) 



Auricula deuticulata et Loweana, Watson, Journ. de Conch. 



220 (1876) 



Habitat Maderam ; rupibus saxicsque sestu maris quotidie 

 submersis adhaereus. Earior. 



It is exceedingly probable that the present Auricula is 

 nothing more than a phasis of the European A. deuticulata^ 

 Montagu ; nevertheless as I cannot be quite sure of this, and it 

 is without doubt the species which was described by Mr. Lowe 

 under the name of Melampus gracilis, I have thought it safer 

 to retain the latter title until the question of its identity with 

 the denticidata shall have been fully established. I possess 

 Mr. Lowe's two original types of his M. gracUis (only one of 

 which, although fractured, is mature), and there cannot be the 

 slightest question whatsoever that they pertain to the species 

 which was published subsequently by Morelet (from Azorean 

 examples) under the name of Auricida vespertincc, and by 

 Pfeiffer (in 1866) under that of Alexia Loweana; so that 

 Pfeiffer was certainly mistaken when he conjectured {Med. 

 Bldtt. xiii. 133), — a conjecture which was unwittingly endorsed 

 by the Baron Paiva (Mon. Moll. Mad. 152) during the follow- 

 ing year, — that the gracilis of Lowe was founded on a mere 

 individual variety of the cequalis. Indeed, apart from all other 

 considerations, its very much smaller size, and the fact of its 

 lower ventral tooth being considerably larger than the upper 

 one (the latter indeed being reduced to a mere tubercle), ought 

 at once to have prevented any such conjecture ; but Mr. Lowe 

 himself was partly answerable for this, inasmuch as he sug- 

 gested (most strangely, as it seems to me) its possibility, and 

 even failed to notice the minute denticle vvithin the outer lip of 

 one of his specimens, — a structure which immediately removes 

 it (independently of its smaller size, less ovate outline, and the 

 proportions of its ventral plaits) from the a^qualis, and affiliates 

 it with a form so nearly allied to the denticidata of Montagu 

 that it is open to consideration whether it does in reality differ 

 from it at all. 



Although totally unconnected with the cequalis, the A. 

 gracilis has nevertheless much in common with the species 

 which I have described above under the name of A. Wcdsoni. 

 It may however be immediately recognized from tlie latter by 

 its rather smaller size, by its more or less denticulated outer lip 

 (the dcTiticle?, whieli are very rarely absent altogether, varying 



