14 Mr. W. C. Williamson on the Recent 



traces of a neck, which appears to wear away with age. Between 

 this common form and that previously described, which I con- 

 sider to be the perfect type, eveiy modification exists. In some 

 forms the costse terminate abruptly near the base of the neck, 

 the superior portion being smooth. This condition obviously 

 connects the L. striata with the var. /3. sernistriata. In others 

 the costse are continued longitudinally along the neck, whilst in 

 a few elegant specimens in the cabinets of Messrs. Bean and 

 Jeffreys they were wound spirally around it. In some examples 

 I have noticed that the neck appeared to be atrophied and 

 wasting, having lost its brittleness and become membranous, as 

 if it were only of use in the early condition of the animal. The 

 character of the decalcified membrane of this species has been 

 already described (p. 8). 



" Reculver, Sheppey, Mr. Walker. Devonshire," Montagu. 

 Exmouth, — Clarke, Esq. Swansea, Rossilly, Manorbeer, Tenby, 

 Oxwich, Caswell Bay, Sandwich, Oban, Kyleakin ; Roundstone, 

 Connemara ; Mr. Jeffreys. Scarborough, Mr. Bean. Boston ; 

 March. Fossil in a miocene tertiary deposit at Petersburg, U. S.f, 

 Dr. Bailey ; also in the English crag, Mr. Searles Wood. 



L. striata, var. a. interrupta, nob. Fig. 7. 



Like L. striata, only the costse are more irregular ; sometimes 

 they bifurcate, at others they are not continued over more than 

 the half or two-thirds of the cell, no two being exactly the same 

 length. The specimen figured represents a common form of the 

 neck when half-gone. 



Swansea, Bossilly, Manorbeer, Tenby, Oxwich, Caswell Bay, 

 Sandwich, Oban; Roundstone, Connemara; Kyleakin. Scar- 

 borough, Mr. Bean. Boston ; March. Not uncommon. 



Lagena striata, var. yS. sernistriata, nob. PI. I. figs. 9, 10. 



Similar in most respects to some young states of L. striata, 

 only the costse arising from the base terminate, some at the lower 

 third, others at the middle, and in one specimen towards the 

 uppermost third of the cell. What has been already said of the 

 smooth neck found in some specimens of L. striata convinces me 

 that this is only a variety. I have seen one specimen wath a mucro 

 at the base approaching the form of L. lavis, var. Amphora. 



Long. T^(j; diam. ^iir- 



* In this specimen nearly the whole of the neck is worn away. 



•f- The same deposit has also furnished examples of £n/o«o/e«2a^/oiosa,^re- 

 thusalactea, Flem,, Renoidea oblonga, Brown (both species of Polymorphhia. 

 D'Orbigny), and what I believe to be young specimens of Roialia Beccarii. 



