fi76 DR. GWYN JEFFREYS ON THE MOLLUSCA OF THE [NoV. 14, 



' Porcupine ' Exp. 18/0: Atl. St. 16, 17, 17a. Several speci- 

 mens. 



Distribution. 'Valorous' Exp., Bay of Biscay (' Travailleur ' 

 Exp. 1881); 1003-1450 fms. Off Culebra I., Danish W. Indies 

 (' Challenger' Exp.) ; 390 fms. 



This is easily distinguishable from any species of Fissurisepta in 

 having a conspicuous and persistent spire, as well as in the shape of 

 the septum. 



The only difference between Puncturella and Rimula seems to 

 consist in the comparative length of the slit. This is proportionally 

 much longer in the young than in the adult of the typical species, 

 P. noachina. 



2. Puncturella noachina, Linne. 

 Patella noachina, L. Mant. Plant, p. 551. 



Puncturella noachina, B. C. iii. p. 257, pi. vi. f . 3 ; v. p. 200, 

 pi. lix. f. 1. 



'Lightning' Exp. : St. 2, 4, 5, off the Faroe I. 



' Porcupine ' Exp. 1869 : St. 6, 9, 13, 14 (and var. princeps ; and 

 var. levior, laterally compressed, keeled in the line of the slit or 

 fissure, and nearly smooth). North Channel, 70, off Lerwick. 1870 : 

 Xi\. 2, 3a, 17, 17a, 24, 27, 28. 



Distribution. From Wellington Channel and Greenland to the 

 southern coast of New England, Iceland, Spitzbergen, and Jan 

 Mayen I. to Scarborough, Novaia Zemblia, Okhotsk Sea, N. Japan, 

 and Corea, Strait of Magellan (Acton and ' Challenger ' Exp.), 

 between C. of Good Hope and Kerguelen I. (' Challenger ' Exp.) ; 

 4-430 fms. 



Fossil. Miocene? : Sicily. Pliocene : Coralline Crag and S. Italy. 

 Post-tertiary : Scandinavia, Scotland, and Yorkshire, Sicily, and 

 Labrador, mostly in "glacial" deposits ; 0-470 ft. 



The odontophore has been well figured by Friele, and shows that 

 it is of a Rhipidoglossan type. 



The genus Cemoria of Leach MS., as defined by Risso, is certainly 

 not the genus Puncturella ; his type is doubtfully referred to the 

 Patella equestris of Linne. 



t/ 3. Puncturella clathrata', Jeffreys. (Plate L. fig. 11.) 



Shell forming an oblong cone, rather solid for its size, opaque 

 and lustreless : sculpture, numerous fine longitudinal striae and 

 stronger concentric ridges, the intercrossing of which produces a 

 cancellated appearance ; the striae do not reach much beyond half- 

 way from the margin, where the ridges become slighter and crowded 

 up to the apex : colour pale brownish white : heah smooth, incurved, 

 twisted a little to the left, and ending in a spire of a single whorl : 

 foramen forming a long triangular slit : mouth oblong : margin finely 

 scalloped : inside smooth and glossy : septum large, triangular as in 

 P. jvofundi. L. 0-15, B. 0-1. 



' Porcupine ' Exp. 1870: Atl. St. l/a. A single and somewhat 

 imperfect specimen, but peculiar and characteristic. 



■■ Latticed. 



