124 Mr. Jeffreys on British Mollusca. 



Turton's specimen in my cabinet, which he is said to have procured 

 from Torbay, and which is referred to in the foot-note at p. 362. vol. ii. 

 of the ' History of the British Mollusca,' I am enabled to state con- 

 fidently that it" belongs to the above species, and not to Terebratula 

 detruncata or decollata, as therein supposed. M. Collard-Descherres 

 records Terebratula truncata as having been taken on the coast of 

 Finisterre (Journal de Conchyliologie, tome ii. p. 393), and there is 

 no reason to doubt the possibility of its being a British species. It 

 is not uncommon in the Mediterranean. Chemnitz cites the Anomia 

 truncata of Midler's Prodromus to the ' Zoologia Danica' as a syno- 

 nym, but I think hastily ; for Muller separates, characteristically as 

 well as generically, Terebratula from Anomia, and his diagnosis of 

 Anomia truncata (" testa suborbiculata, obsolete striata, cardine 

 trUncato") may equally apply to a variety of A. patelliformis. 



Argiope decollata. Anomia decollata, Chemn. viii.t. 78. f. 705. A. 

 detruncata, Gmelin, 2347. Orthis (changed from Terebratula) de- 

 truncata, Phil. ii. 69. Of this fine and interesting species I found a 

 few perfect specimens, of different ages, and two single valves in 

 dredged stuff from Guernsey. The size of my largest specimen is 

 nearly one-third of an inch square. These have not the normal form 

 of the species, and resemble a horse's hoof in shape, being longitudi- 

 nally oval, instead of transversely oblong (as in Mediterranean exam- 

 ples) ; and the ribs are much fainter and do not extend to the front 

 margin. Specimens in Mr. M'Andrew's collection from Madeira 

 (though smaller than ours) have the same form and sculpture. 

 These may therefore belong to a distinct and undescribed species. 

 A representation will be found at PI. Y. fig. 3 a-e. The specific 

 name of decollata, given by Chemnitz, has priority over that of de- 

 truncata, which Philippi adopted from Gmelin, the latter author 

 having erroneously cited Chemnitz as the authority for his name. 

 The species was first indicated by Gualtier ; but he did not designate 

 it by any specific name, although his description is not bad com- 

 pared with his drawing, which is abominable. 



A. eistellula, ii. 361 (Megathyris) and iv. 257. Not uncom- 

 mon in the coralline zone at Guernsey, Dr. Lukis having taken 

 upwards of 200 specimens from a single stone. I erroneously re- 

 ferred this species in my paper on Piedmontese Testacea to the 

 Orthis Neapolitana (seminulum, olim) of Philippi ; but having since 

 had the opportunity of examining a great number of specimens, I 

 am satisfied that the two species are distinct. The Orthis Neapoli- 

 tana differs from our species in being longitudinally instead of trans- 

 versely oval (although individuals vary considerably in this respect), 

 in the foramen being smaller, and in the hinge-plate being contracted, 

 and not (as in A. eistellula) extending the whole breadth of the 

 shell ; in the papillae which encircle the interior margin of each valve 

 being much less numerous and more prominent ; as well as in the 

 internal rib of the under or flat valve being strongly serrated. It 

 also attains to twice the size of A. eistellula. I have little doubt 

 that Philippi' s species will be found in the Channel Isles or on the 

 south coast of England. Mr. Davidson (in his excellent monograph on 



