100 Hogg, on the Lingual Membrane of Mollusca. 



slender body lies curled up, and even then is insufficient to 

 protect it from the assaults of an enemy. The teeth of the 

 two, however, differ in some important particulars. Those 

 of Limax are arranged in very numerous straight rows, the 

 central one in each of which is the typical tooth, the others 

 passing through certain modifications of form and character 

 as they approach the outermost edge of the band. The 

 whole odontofore is broad, and nearly as wide as it is 

 long; the number of teeth in each row almost equals the 

 number of rows the total of which, in the fully grown slug, 

 reaches, according to Thomson, the enormous number of 

 28,000. The teeth are very minute, requiring a magnifi- 

 cation of at least 200 diameters to resolve the finely curved 

 sjiines, which are obviously intended only for rasping vege- 

 table matters. The odontofore of Testacella maugei (fig. 80) 

 offers a contrast ; it is large and wide, furnished with 

 not more than fifty semicircular rows of teeth, gradually dimi- 

 nishing in size as they approach the central row, the median 

 teeth being the smallest, almost rudimentary in their cha- 

 racter. The outermost teeth on the band are of great 

 strength, barbed and sharply pointed at the extremity, 

 broader towards the base, and furnished with a nipple-like 

 process which serves the purpose of a kind of lever attach- 

 ment to the tooth, and connects it with the basement mem- 

 brane. A set of powerful muscles preside over this organ of 

 destruction, and thus the little animal is enabled to erect its 

 teeth and plunge them into the body of its victim. 



It may be said to admit of a doubt whether the voracious 

 feeding Cephalopods are rightly placed by G ray — whether Sepia 

 officinalis (fig. 22), with its contractile proboscis, prehensile 

 spiny collar, and odontofore furnished with fifty rows of 

 shark-like teeth, its gizzard for trituration, and its crop for 

 storing, all implying a higher degree of organization, can be 

 classed with such families as Paludinidse. Another carnivo- 

 rous species, though not resembling the Cephalopod in gene- 

 ral characters and modes of pursuit and destruction, are not 

 the less equally inimical to the mussel and other shell- 

 fish — the whelk family. 



The odontofore of Buccinum undatum is a rather lonsr, 

 narrow band, bearnig a hundred rows of teeth, the medians 

 of which are crested with points bent upon themselves ; the 

 laterals are similar, but smaller, hooked and tipped with 

 silica. The proboscis is cylindrical, and armed with sharp, 

 slender spines, which enaliles the animal by a succession of 

 strokes to penetrate the hardest shell, and in a short time 



