342 LITTORINIDJE. 



size, resulting from the various complicated incidents attached 

 to habitat. 



I omitted to observe that the Littorime are destitute of 

 head- and neck -lappets, and that the operculigerous lobe is 

 small, simple, and not co-extensive with its organ. 



L. RUDIS, Donovan. 



L. rudis, Brit. Moll. iii. p. 32, pi. 83. f. 1, 2, 3, 5, 6, 7, & pi. 86. f. 1. 

 L.patula, Jeffreys, Brit. Moll. iii. p. 36, pi. 85. f. 6-10; (animal) 



pi. G.G. f.2. 

 L. tenebrosa, Mont,, Brit. Moll. iii. p. 39, pi. 84. f. 11, 12, & pi. 85. 



f. 1-5. 



L. saxatilis, Johnston, Brit. Moll. iii. p. 43, pi. 86. f. 4, 5. 

 L.fabalis, Turton, Brit. Moll. iii. p. 49, pi. 86. f. 2, 3. 

 L.palliata, Say, Brit. Moll. iii. p. 51, pi. 84. f. 8, 9, 10. 

 L. zonaria, L. rudissima, L. jugosa, L. neglecta, Auct. 



This well-marked species has nearly the same organs as 

 L. littorea ; I have compared the nervous ganglions and other 

 internal parts of both forms, without finding distinction. To 

 enumerate the greater part of the other organs, in comparison 

 with those of L. littorea, would be a repetition ; I will only 

 mention the essential specific distinction, which is, that in 

 the females of this species the large bulky ovarium is usually 

 filled with strings of testaceous pulli, that is, if examined 

 at the season when, O ! Alma Venus, they are " perculsse 

 corda tua vi," the ovaries fill up the tumid antepenultimate 

 volutions. The markings and colours of the animal have the 

 same character as those of Littorina littorea, except that they 

 are much less intense ; but though closely allied, it is parti- 

 cularly distinguished by the much higher littoral level of its 

 habitat, the greater tumidity of the volutions, by the colour, 

 and, above all, by the very different ovarium, its contents and 

 mode of reproduction. It rarely exceeds an inch in length, 

 and | of an inch in diameter. 



To describe the varieties enumerated above, which are the 

 pseudo-species of authors, would be to say, that the organs of 

 all, both internal and external, do not vary in the slightest 

 degree in form; the only differences are modifications of 

 colour, size, and in the striae, depending entirely on habitat. 



