HARGREAVES : MARINE MOLLUSCA OF~ YORKSHIR6 COAST. 91 



1907 in its recorded habitat on Filey Brig, but without success. 



Littorina rudis (Maton). — Very common. 



var. saxatilis Johnston. — Staithes (J.H.) ; Scarborough 

 (W.C.H.). 



var.jugosa Montagu. — Staithes (J.H.); Whitby (Prof. Cockerell). 

 var. patula Thorpe. — Scarborough (Marshah) ; not uncommon, 

 South Bay, Scarborougii. 



var. tenebrosa Montagu. — Hayburn Wyke (D.). 



Littorina littorea (Linne). — Dogger Bank, drifted (L. & M.) ; 

 Redcar, very common (I).F.); Saltburn (M.L.T.); Staithes (J.H.); 

 Sandsend, very common (M.V.L.) ; abundant along the coast, Scar- 

 borough and Filey, and gathered largely for sale. A bright red form 

 occurs both north and south of Scarborough ; Withernsea ; Wall 

 Creek to Spurn; Kilnsea Skerries (T.P.). 



Rissoa parva (daCosta). — Redcar (W.C.H.) ; Saltburn (J.H.) ; 

 very common, Sandsend (M.V.L.) ; the most abundant of our Jiissoas. 

 At certain times may be had in thousands from seaweed and stones 

 in pools. 



var. interrupta Adams. — Saltburn and Redcar (J.H.); more 

 common than the type, Sandsend (M.V.L.) ; also at Scarborough and 

 Filey in similar proportions. 



var. exilis Jeff. — Very rare, Scarborough. 



var. semicostata Marshall. — Frequently at Scarborough. 



Rissoa inconspicua Alder. — Dogger Bank (Brady, Howse); 

 Scarborough (Bean). 



Rissoa guerini var. costulata Alder.— Scarborough (Bean). 



Alvania punctura (Montagu). — Dogger Bank (L. & M.) ; Red- 

 car (J.H.) ; fairly common in shellsand, Sandsend (M.V.L.) ; alive in 

 both bays, Scarborough ; and fairly common in shellsand, Scarborough, 

 Filey and Bridlington. 



Manzonia COStata (J. Adams). — Two in shellsand, Sandsend 

 (M.V.L.); several in shellsand, Scarborough; Scarborough (Bean). 



Onoba striata (J. Adams). — Dogger Bank (L. & M.); Redcar 

 (J.H.) ; extremely common in shellsand, Sandsend (M.V.L.); next 

 to parva, our commonest Rissoa; it may be taken alive at low water 

 mark rarely, and it is abundant in shellsand, Scarborough, Filey and 

 Bridlington; Withernsea (T.P.). 



var. aculeus Gould. — Very common in shellsand, Sandsend 

 (M.V.L.); and also at Scarborough and Filey. 



Hyala vitrea (Montagu). — Scarborough (Bean) ; one in shell- 

 sand, Scarborough. 



Setia obtusa (Cantraine). — Dogger Bank (Marshall) ; Scar- 

 borough (Bean). 



