232 Panama Shells. 



Deshayes observes that he can hardly think that the shell 

 figured as Calyptrcea unguiformis by Broderip in ' Trans. Zool. 

 Soc.' I. pi. 29, f. 4, is the shell of Linnaeus. He says the shell 

 of Linnaeus is distinguished by a profound notch at one 

 extremity of the partition, and a feebler one at the other ; that 

 the shell described by Mr. Say as Crepidula plana wants this 

 notch, and is the shell figured by Broderip. Now it so happens 

 that the only specimen which I am certain is entire, has this 

 notch precise^ as described, and the tooth-like process which 

 separates the large notch from the rest of the margin is such as 

 would be likely to be broken in almost every instance. This 

 fact leads me to suppose that all three of the shells in question 

 arc of the same species, and should be called C. unguiformis" 



Station. Dans 1'interieur des coquilles univalves abandonne'es ; 

 Defrance. Espece qui a 1'habitude de se mettre a 1'abri dans 

 les coquilles abandonnees ; Deshayes. Inside of dead shells of 

 Ranella vexillum, R. ccclata, &c. * * * Dredged from sandy mud 

 at a depth ranging from 4 to 10 fathoms ; Cuming ! Broderip. In 

 the aperture of other shells ; Gould ! In dead shells, whether 

 or not the shells are occupied by Paguridse. We have received 

 the shell from Sicily in the aperture of a Murex trunculus. In 

 Massachusetts we have found it in the aperture of Natica dupli- 

 cata, of Pyrula canaliculata, P. carica ; on the inside of Pecten 

 concentricus, and of the crustacean Limulus polyphemus, &c. 

 In Jamaica, we found it in Murex brevifrons, M. funiculatus (f), 

 Fasciolaria tulipa, Pyrula melongena, Turbo crenulatus, &c. 

 In Panama we found it in Murex radix, Fasciolaria granosa, 

 Turbo saxosus, Natica sp. indet., &c. It occurs more frequently 

 near half tide level, but is not very narrowly limited in its ver- 

 tical range. 



Dr. Gould and D'Orbigny both consider the peculiarities of 

 this shell as the effect of its position ; and Orbigny ascribes the 

 flattened form to the pressure of the organs of hermit crabs, 

 one of which usually occupies the same habitation. If ; however, 



