CANALIFERA. MOLLUSCA. PYRULA. 295 



horizontal one, all terminating in a pointed apex, and forming a 

 winding terrace up the spire ; covered with a dense yellowish- 

 brown epidermis, bristling with stiff, curved hairs along the lines 

 of growth, and at regular intervals corresponding with the revolv- 

 ing lines of the shell ; aperture ovate, three fourths the length of 

 the shell, the outer lip simple, sharp, and arched ; the inner margin 

 concave and twisted as it turns out to form the canal, smooth and 

 enamelled ; within, brightly polished, variously shaded witt chest- 

 nut and fawn-color ; operculum small for the shell, oval, the apex 

 at the lower extremity, its elements coarse, strengthened on the 

 inner side by a varnished deposit. Ordinary length 6 inches, 

 breadth 3 inches. 



Found about Nantucket, Martha's Vineyard, Buzzard's and 

 Narraganset Bays. It is set down, in all the works I have seen, 

 as an inhabitant of the arctic seas, and Canada. But Cape Cod is 

 probably its northernmost limit ; at least, I have never heard of it 

 farther north. I believe too, that it does not extend far south. 



It seems superfluous to be minute in the description of a shell which 

 would at once be recognised, when we have said that it is a large, 

 pear-shaped shell, with its peculiar channel at the suture, and each 

 whorl crowned with a beaded circlet. It is subject, however, to con- 

 siderable variations. It varies in color, from light-orange to livid- 

 brown. In thickness, also, there is great diversity. In the old shells, 

 the nodules, which are so regular in the young, are worn off, and they 

 seldom exhibit more than vestiges of the bristled epidermis. The 

 largest specimen I have seen is seven inches in length. Kiener, like 

 his predecessors, has associated two shells under the same name, 

 which are certainly distinct, and probably come from different quar- 

 ters of the globe. Which should be held as the M. canaliculdtus of 

 Linnaeus, must remain uncertain, since the essential character of his 

 species is, a canal intervening between the whorls at the suture (" quod 

 anfractus in spira non contigui sunt, sed canali distantes"), a character 

 which belongs to both species. Gualter and Davila evidently had 

 reference to our shell alone. 



The ova are contained in membranous cases, about the size and 

 thickness of a cent. Great numbers of these are united together in a 

 parallel position, about one fourth of an inch apart, by a ligamentous 

 thong attached to their edge, so as often to form strings a yard in 

 length, gradually diminishing in size from one end to the other. They 



