320 trochid^:. 



son, I have seen deposited on the foot, and they may 

 possibly feed on and destroy it." I shonld be disposed 

 to attribute the malformation to an epidemic disease of 

 the operculigerous lobe. It also occurs in Buccinum un- 

 datum, the fry of which are separately enclosed in 

 capsules, and are therefore incapable of feeding on the 

 maternal operculum. Besides, all the specimens, male 

 and female, are affected in the same manner. T. lineatus 

 may be known from its congeners by its size, colour, 

 tooth, and peculiar umbilicus; and the periphery is 

 never angulated. 



Pulteney described it as T. crassus, and the young as 

 T. lineatus. Monodonta articulata of Lamarck and M. 

 Draparnaudi of Payraudeau are closely allied to the pre- 

 sent species, if all of them are not the same. T. lineatus 

 of Lamarck is a New Holland shell. According to 

 Bouchard-Chantereaux, ours is the T. punctulatus of De 

 Blainville. T. (Monodonta) sitis of Recluz appears to be 

 the young of the European shell. 



E. Spire pyramidal ; base imperforate ; pillar-lip notched or 

 angulated at the lower part. Ziziphinus, Leach. 



10. T. Montacu'ti*, (Montagui) W. Wood. 



T. Montagui, Wood, Ind. Test. Suppl. pi. 6. f. 43; F. & H. ii. p. 511, 

 pl.lxv. f. 10, 11. 



Body yellowish-white, speckled with purplish-brown and 

 milk-white flakes : mantle thin and semitransparent, marked 

 with greenish spots ; lappets large in proportion, forming two 

 saucer- shaped lobes, one on each side of the tentacles ; both 

 these lobes appear plain, although of different sizes: head 

 semicylindrical, with the front edge minutely notched; veil 

 bilobed, scarcely perceptible: tentacles slender, sometimes 

 finely pointed, in other examples having club-shaped tips: 

 eyes rather large, on short hairy tubercles : foot lanceolate and 

 thick, rounded in front, with somewhat angular corners, and 



* Another tribute to the memory of Col. Montagu. 



