122 JOURNAL OF CONCHOLOGY, VOL. 9, NO, 4, OCTOBER, 1898. 



size, colour, and shape, though usually oval. There are two distinct 

 forms, one shaped as the type, the other larger and oval. Besides the 

 purple furrows, it occasionally has a dusky broad band round the 

 periphery. It is not always yellow, being sometimes red or brown, 

 and the purple furrows are often absent. Donovan gave it the 

 expressive name of nigrolineata. 



Var. patula Jeffr. — Smaller, more or less finely ribbed. Guern- 

 sey; Torbay ; Scarborough. The type sometimes has an expanded 

 outer lip resembling this variety, but this is thinner and has a larger 

 aperture. 



Var. globosa Jeffr. — Jersey and Guernsey. Usually lives on 

 stony causeways. A subscalariform colony occurs at Jersey on some 

 oozy mud flats. It is the var. rudissima of Bean, and I consider the 

 name should have been retained. 



Var. tenebrosa Mont. — A dwarf form is very abundant in 

 Tilbury Marshes, and a still smaller form, not exceeding a line in 

 length, has been taken by Mr. Duprey and myself in sea-weeds at 

 Jersey, very low down. The latter are especially remarkable, as var. 

 tenebrosa does not live on the open coast, but usually near the mouths 

 of rivers and near high-water mark. The shell is occasionally shaped 

 as the type, but it is always thinner, with a deeper suture. 



Var. similis Jeffr. — Channel Islands, Guernsey especially 

 Exmouth ; Torquay. 



Var. laevis Jeffr. — Guernsey; Weymouth. 



Var. compressa Jeffr. — Herm Island ; Torbay ; Tenby. This 

 is like an elongated form of var. sulcata, and differs from the unicolored 

 examples of that variety in being longer and narrower. 



All the above varieties merge one into the other, and sometimes 

 two or three of them are combined, such as tetiebrosa-patula, com- 

 pressa-jugosa, jugosa-similis, &c. The var. saxatllis is especially mixed 

 up with other dwarf varieties. 



For such a common species monstrosities are rare, and yet they are 

 liable, living as they do on rocky and stony shores, to numerous 

 accidents. One cause of monstrosities, as I believe, is the over- 

 crowding of fry in the bodies of the parents ; but although L. rudis 

 has a formidable progeny to carry, they all seem to come forth without 

 any accidents. I have a fine series of " mends " of this species, but 

 have met with very few distortions or monstrosities. An exception, 

 however, must be made in respect to a numerous colony of the var. 

 tenebrosa, taken by Mr. Sykes from a piece of brackish water near 

 Weymouth, where the monstrosities greatly exceeded the typical 

 specimens, and were characterised by the whorls being more or less 

 disconnected, and many of them depressed like a Planorbis. Several 



