LITTORINA. ddl 
nucleus. The buccal apparatus is a deep-red fleshy mass, 
supported by two thin coriaceous plates, between which, in 
ordinary-sized animals, a long (at least 2 inches) riband-like 
white spmy tongue issues, passing down the cesophagus, and 
becoming closely coiled in the stomach; its termination is 
tinged with red. Immediately behind the buccal mass is the 
cesophageal cordon, which consists of only two white, subro- 
tund, flattish ganglions, one on each side; and behind them 
are the salivary glands, each formed of a mass of foliaceous 
granules. There is only one branchial plume, of light yellow, 
attached to the left side of the mantle and neck of the animal. 
The verge is a large flat organ, grooved longitudinally, ridged 
transversely, dentated on one side with two points, one below 
the other, the lower one with a minute orifice: the female is 
oviparous. The antepenultimate whorls are always flat in 
this species, bemg a condition resulting from the shape and 
size of the ovarium, which is only adapted for ova; it is, 
however, much more prolific than the Littorina rudis and 
varieties. 
This is the common edible periwinkle of the London 
markets, and the only one, as the females of the L. rudis and 
all its varieties are viviparous, and cannot be used for food in 
consequence of the grittiness arismg from craunching the testa- 
ceous pulli; it is found in all situations, often exposed to the _ 
full influences of an open sea, but more usually in estuaries 
and muddy inlets, which are also the habitats of certain 
varieties of the L. rudis; it grows to 14 inch in length and 
1 inch in diameter, 
The pectinations of the branchial plume of nearly all the 
Littorine, instead of being 16-20, vary from 45-60; they are 
pale brown, long, slender, and close-set; an examination 
under the microscope sanctions this correction. Having re- 
peated a series of fresh observations on some hundreds of the 
Littorina rudis in comparison with the L. tenebrosa and 
L. jugosa of authors, I am authorized to say, that the identity 
in figure and action of their ternal and external organs has 
further satisfied me of the propriety of regarding them as 
varieties of the L. rudis; the only differences are colour and 
