1882.] 'lightning' AND 'porcupine' EXPEDITIONS. 677 



Distribution. Off Culebra I. (' Challenger ' Exp.) ; 390 fms. 



It differs from the young of Fissurella grcBca, which it resembles 



in shape, in having not only a different kind of cancellation but 



especially an internal septum. 



/ 1. Fissurella grjeca, Linne. 



Patella grceca, L. S. N. p. 1262. 



F. grceca, B. C. iii. p. 266, pi. vi. f . 4 ; v. p. 200, pi. lix. f, 5. 



' Lightning ' Exp., St. off the Faroe I. 



' Porcupine' Exp. 1870 : Atl. St. Vigo B., 24, C. Sagres, Tangier 

 B. ; Med. G. Tunis. 



Distribution. Shetland {Fo7-bes) to the Archipelago and Egypt, 

 Adriatic, Mogador, Madeira, Canaries ; 0-95 fms. 



Fossil. Miocene: Vienna Basin and Switzerland {Homes) 1 

 Pliocene: EngUsh and Belgian Crags, Transylvania, S. France, N. 

 Africa, Italy, Morea, Rhodes. Post4ertiary : England and Ireland, 

 Sicily, Ischial.; 0-1360 ft. 



Varies greatly in the sculpture : in some specimens it is strong, 

 coarse, and sparse; in others fine and close. Very young shells have 

 no foramen or slit, but a prominent spire. I have a monstrosity 

 which grew and lived in the Hamburg aquarium ; after commencing 

 in the usual way, it became expanded and was composed of laminfe 

 like those of a common oyster. Linne evidently included several 

 species in his F. grceea, as is shown by his citations of Lister, 

 Adanson, and Gualteri. 



There are several obsolete and questionable synonyms. 



(/ 2. Fissurella gibberula, Lamarck. 



F.gibberula, Lam. An. s. Vert. vi. (2) p. 15 (1822). 



• Porcupine ' Exp. 1870 : Med. St. Benzert Road, Rasel Amoush. 



Distribution. Brittany to the Archipelago and Egypt, Adriatic, 

 Canaries (McAtidrew), Guinea (Dunlcer), Panama (P. Carpenter) ; 

 0-120 fms. 



Fossil. Pliocene : Italy. Post-tertiary : Sicily ; 0-22 ft. 



I am by no means satisfied that this so-called species is more than 

 a dwarf variety of F. grceea. Many intermediate forms occur. 

 The size of the foramen and the degree of gibbosity are unreUable 

 characters. 



Perhaps the present species may have been the long-lost or doubt- 

 ful Patella pustula of Linne, which is described as " gibboso-con- 

 vexa." The word " preecedenti " might have been a mistake for 

 " sequenti," viz. to P. grceea instead of P.fissura, because the other 

 characters belong to Fissurella and not to Emarginula. However, 

 it is not the F. pustula of Lamarck. 



F. gibba of Philippi (1836), and a few other synonyms. Gibbus 

 is a classical word, not gibberulus. 



[/^. Fissurella nubecula, Linne. 



Patella nubecula, L. S. N. p. 1262; Martini, Conch. Cab. i. 

 t. 12. f. 105. 



' Porcupine' Exp. 1870 : Atl. St. Vigo B. 



