1882.] ‘LIGHTNING’ AND ‘ PORCUPINE’ ©XPEDITIONS. 677 
Distribution. Off Culebra I. (‘ Challenger’ Exp.) ; 390 fms. 
It differs from the young of Fissurella greca, which it resembles 
in shape, in having not only a different kind of cancellation but 
especially an internal septum. 
y 1. FissureELLA GRa&cA, Linné. 
Patella greca, L. 8. N. p. 1262. 
F. greca, B. C. iii. p. 266, pl. vi. f. 4; v. p. 200, pl. 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 (Forbes) to the Archipelago and Egypt, 
Adriatic, Mogador, Madeira, Canaries ; 0-95 fms. 
Fossil. Miocene: Vienna Basin and Switzerland (Hérnes)? 
Pliocene: English and Belgian Crags, Transylvania, 8. France, N. 
Africa, Italy, Morea, Rhodes. Post-tertiary : England and Ireland, 
Sicily, Ischia I.; 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 laminze 
like those of a common oyster. Linné evidently included several 
species in his F. greca, as is shown by his citations of Lister, 
Adanson, and Gualteri. 
There are several obsolete and questionable synonyms. 
2, FissURELLA GIBBERULA, Lamarck. 
FF. 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 (McAndrew), Guinea (Dunker), 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. greca. Many intermediate forms occur. 
The size of the foramen and the degree of gibbosity are unreliable 
characters. 
Perhaps the present species may have been the long-lost or doubt- 
ful Patella pustula of Linné, which is described as “‘ gibboso-con- 
vexa.”” The word “ precedenti” might have been a mistake for 
 sequenti,” viz. to P. greca 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. 
.-3. FissuRELLA NUBECULA, Linné. 
Patella nubecula, L. S. N. p. 1262; Martini, Conch. Cab, i. 
Caltade VOD. 
‘ Poreupine’ Exp. 1870: Atl. St. Vigo B. 
