22 TEREBRATULID.E. 



The beak resembles that of Lingula. Very young 

 shells are not tuberculated. This species cannot be mis- 

 taken in any stage of growth for the fry of Terebratula 

 caput-serpentis, which are of quite a different shape, 

 and more inequivalve than the adult. I have specimens 

 of the fry of that species only half the size of A. cap- 

 sula. The fry of T. cranium, which I have taken of 

 even a smaller size, have a longer and more slender 

 shell, and the valves are decidedly unequal. From the 

 young of A. cistellula the present species may be distin- 

 guished by being of a regularly oval shape and more 

 convex in every part, but especially by the contracted 

 hinge-line and comparatively small aperture. 



Professor King proposed to make this species the type 

 of a new genus, which he named Gwynia, out of com- 

 pliment to me ; but although I duly appreciate the 

 intended honour, I cannot conscientiously accept it. 

 Although the species is unquestionably distinct from 

 any of the foregoing, it may be the young of A. Neapo- 

 litana (probably T. cordata of Bisso) ; and I feel pretty 

 confident that the last-named species will be found on 

 our own as well as the Mediterranean coasts. 



Terebratella (or Megerlea] truncata has but a very 

 slender claim to be admitted into our fauna. Dr. 

 Turton's cabinet contained a specimen bearing, in his 

 handwriting, the name of " Terebratula caput serpentis" 

 and the locality " Torquay." It is not uncommon in 

 the seas of southern Europe ; and according to Collard 

 des Cherres it has been found on Caryophyllia at Quim- 

 per. In a footnote to the ' British Mollusca ' (vol. ii. 

 p. 362) this species has been accidentally mistaken for 

 Argiope decollata, with reference to Turton's shell. 



I am by no means satisfied that Rhynchonella psit- 

 tacea still inhabits the British seas, although there is 



