MARSHALL: ADDITIONS TO BRITISH CONCHOLOGY. 23I 



Nassa reticulata L. — Some specimens from Jersey are inter- 

 mediate between the type and var. nitida. A short-spired .form (var. 

 curia B. I), and D.) occurs on the South Devon coasts, and has 

 corresponding forms in the next two species. The denticulations of 

 the aperture are periodical marks of growth only, and not of 

 maturity, a similar peculiarity obtaining in our other species of Ahissa 

 as well as in Purpura lapiilus. 



var. minor Marsh., /r;//;7^. of Condi., 1893, vol. vii., p. 26 1 . — Coll. 

 Clark (Jeffreys), and Torbay. This has the proportions of N. pygmaar, 

 while an immature typical specimen of the same size is more conical 

 and stumpy, and clearly indicates its immaturity. 



var. nitida Jeff. — Hunstanton (Mayfield) I Falmouth (Norman 

 and J. T. M.) ; Southampton Water. Tliis was described and figured 

 in Britiih Conchology as a distinct species, but met with no acceptance, 



N. incrassata Strom. — Variable in size, sculpture, and length of 

 spire. Dredged specimens are always much smaller than those 

 living between tide-marks. An e.xample from Scilly is pure white. 



var. major Jeff. — Chappie Island, Bantry Bay (Span) ! This 

 variety is only a line longer than the type, but it bulks largely. 

 L. o'6in., b. 0*4. 



var. minor Jeff.— Generally distributed, but mostly dredged. 

 Scilly Isles, Land's End, Torbay, Scarborough, Buiidoran, Achil 

 Island, Dornoch Frith, Loch Boisdale, &c. Usually two lines in 

 length, but some specimens from Torbay are still smaller. 



var. simulans Jeff — Occasionally with the type, though rare 

 and solitary. Guernsey, Scilly Isles, Weymouth, Scarborough, 

 Killalla Bay, Sound of Sleat, Baria. Typical specimens frequently 

 have a varix on one of the topmost whorls. 



N. pygmaea Lam. — Some of the forms of this species run 

 remarkably close to N. incrassiita. Usually the whorls are less 

 tumid, the suture shallower, and the crossings of the cancellated 

 sculpture produce granulations instead of tubercles, while the young 

 are more polished and not so angular at the base. Very rarely the 

 shell is minus the specific varicose rib, and in a few cases the 

 sculpture is regularly reticulated, the longitudinals and spirals being 

 equalised and forming square spaces. Gwyn Jeffreys' figure is a good 

 outline, but it exhibits the sculpture coarser than iV". incrassata 

 instead of finer. 



{To he continued^. 



