70 THE PEOCEBDINaS OF THE LINNEAN SOCIETY 



irregular longitadinal folds on the outer edge of tlie lip. The 

 aperture is small, round, but somewhat irregular ; is highly- 

 enamelled, a deep purple brown color, and there are two spira 1 

 yellowish lines running up the throat, one at the base or anterior 

 as already described in other Littorince, and the other between 

 the sutare and the posterior line of tubercles, but just at the 

 edge of the latter. The columella is very much depressed, 

 sharp, as in all the genus, dilated and almost channelled at the 

 anterior end. The color is a bluish grey, the tubercles white, 

 and the spire reddish. In all matters of detail it is absolutely a 

 Littorina. It is often spirally striated. The operculum is of 

 four neat ovately rounded whorls, and not quite so marginal as 

 in our other species, but still almost posterior, and at the 

 columellar edge. The lingual ribbon lies in a coil at the back of 

 the head. The coil is very conspicuous and round, whereas in 

 L. ccBYulescens it is not so easily seen when the animal is drawn 

 out of its shell, as the coils are fewer, oval, and the membrane 

 which covers it is thicker. The teeth on the ribbon are like all 

 the genus, but it seems to me that the radula itself is broader 

 and longer. The organs of respiration and reproduction call for 

 no especial notice, except that they are on the typical plan of 

 Littorina littorea. The muscular tissue of the body is thin and 

 transparent, and very favorable for microscopic examination. 

 The nervous ganglia and the neural branches are very plainly 

 visible by transmitted light with an inch objective. 



With the exception of the shell there is nothing to separate 

 the species from the typical Littorina. Messrs. Adams separates 

 it, and probably also Gray, on the ground of the tuberculations 

 on the shell. They notice other differences, such as a callosity 

 on the anterior lip generally, and a few-whorled operculum 

 which has also a broad membranaceous edge. Whether these 

 particulars apply to all the members of the genus except this one 

 I cannot say. They do not apply to this. The operculum has 

 four whorls, but there is no membranaceous edge, such as is 

 very visible in our Trochocochlea, and there is no callosity on the 

 lip. And I respectfully submit that if they were there they are 

 not sufficient as generic distinctions. They are at most sub- 



