1882.] ‘LIGHTNING’ AND ‘PORCUPINE’ EXPEDITIONS. 669 
more raised and oval at the sides; under a microscope can be 
detected numerous and close-set lines or strie, which are arranged 
lengthwise : colour whitish: beaks none, except on the tail-plate, 
where they are nearly circular: inside glossy. LL. 0°1, B. 0°05. 
‘Porcupine’ Exp. 1870: Atl. St. 3a, 17. Two specimens. 
Although this is a very small species, and might be regarded as 
the young of some other species, I must observe that I have care- 
fully compared both specimens with the young of all other European 
species of Chiton known to me, and some specimens of which last 
mentioned species are much smaller than those which I have now 
described. The peculiar character of having so very few and scattered 
tubercles is not presented by any other of those species. The girdle 
is membranous and thin. 
9. CHITON MARGINATUS, Pennant. 
C. marginatus, Penn. Brit. Zool. iv. p. 71, t. xxxvi. f. 2; B.C. 
iii, p. 221; v. p. 199, pl. lvi. f. 5. 
‘Porcupine’ Exp. 1870: Atl. St. Vigo B. 
Distribution. Greenland (coll. Moller, in mus. Copenhagen), 
Faroe I., Norway to Mogador, Mediterranean and Adriatic, eastern 
and western coasts of North America; 0-40 fms. 
Fossil. Pliocene: Sicily (Monterosato). Post-tertiary : Norway, 
Selsea ; 0-100 ft. 
C. cinereus of Laskey, Lowe, and Forbes and Hanley (not of 
Linné), C. variegatus of Philippi and other authors, and C. dentiens 
of Gould. 
D. Lophyrus, Poli. 
Girdle imbricated or regularly granular. 
10. Curron asus, Linné. 
C. albus, L. S. N. p. 1107: B. C. ii. p. 220; v. p. 199, 
pl. lvi. f. 3. 
‘ Lightning’ Exp. ay Obs Ly 2, Os 
Distribution. Spitzbergen, Novaia Zemblia, Russian Lapland, 
White Sea, Finmark southward to Isle of Man, Faroe Isles, Iceland, 
Greenland, Wellington Channel, Behring Strait, eastern and western 
coasts of North America; 0-337 fms. 
Fossil. Post-tertiary : Fort William. 
Family I]. Parevuipa. 
* PavTELLA VULGATA, Linné. 
P. vulgata, L. 8. N. p. 1258: B.C. iii. p. 236, pl. v. f. 3; v. 
pl. lviii. f. 1-4. 
‘Porcupine’ Exp. 1869, St. Donegal B. 1870: Atl. Gibraltar B. 
Distribution. Throughout the western coast of Europe from the 
Faroe Isles and Bergen to Gibraltar, as well as the Mediterranean 
and Adriatic; between tide-marks and even above high water, on 
