MOLLUSCS. 



333 



Fig. 415. - 



■ Jiuccinwn undatum, 

 ■whelk. 



a canal, a smooth columella, and an untoothed outer lip. The most common species is 

 the whelk, £. undatum, common to the northern Atlantic shores of Europe and Amer- 

 ica. It burrows in the sand below low-water mark. Its 

 eggs are laid in hemispherical capsules, yellow in color, piled 

 up in a heap, and presenting an appearance well described 

 by the name ' sea-corn ' applied to them by the New England 

 fishermen. In England they are called 'sea wash-balls' 

 from the fact that they are employed in washing the hands, 

 their parchment-like texture tending to scour away the 

 dirt. Each capsule, when first laid, contains a number of 

 eggs, but of these but few develop, the others being swal- 

 lowed by the young which have got a little start in devel- 

 opment. In this respect, they are like the young spiders. 



In America, the whelk is not used as food, but in Eng- 

 land large numbers are brought to the market, the annual 

 catch at Whitstable (a small village at the mouth of the 

 Thames) being worth, in 1866, £12,000. Although the 

 shell of the whelk is stout and strong, it is eaten in great 

 numbers by the larger bottom-feeding fishes, some of which 



r ^^^^^^^m are furnished with teeth strong enough to crush the shell 



^^^H^^^^H like a stone breaker, while others bolt shell and all whole, 

 ^EJ^x leaving the gastric juices the labor of dissolving the 



^^^ M ^^^H nutritious portions. 

 KKmr-^.-^^ IH^^I Besides the common Buccinum zindatum, several 

 other species are found in the north Atlantic, north of 

 the New England shores. One of these boreal forms, £. 

 ciliatum, is figured; the differences between this and the 

 common whelk are evident. Most of the specimens in 

 collections are obtained from the stomachs of fishes caught 

 on the Grand Bank. 

 I '^HHH| M^SM'' ' \ The genus Eburna embraces the ivory shells, so called 



fc__^m ^^^7 \ from the color and texture of some of the forms. In the 



^^K ^mti-^W / 'io^^'^ oriental species comprised in the genus, the shell 



^^^ W' / is thick, deeply umbilicate, the columella and outer lip 



L V . ^^ without folds or teeth, and the suture between the whorls 



¥ia. tie.— Buccinum cUiaivml''' channelled. The surface of the shell is ivory white, 



spotted with an orange red. The animals usually move 

 along at a leisurely pace, but when alarmed they are capable of much quicker motions. 

 They frequent muddy bottoms where the water is ten or twelve fathoms in depth, and 

 are caught in considerable numbers in the nets of the Chinese fishermen, who use 

 them as food. 



Nassa contains a large number of species divided up into the sub-genera, Ilyanassa, 

 Tritia, etc. The general shape and appearance may be seen from our figures, a com- 

 mon character being the tooth or plait at the upper part of the columella, much 

 more marked in some species than in others, and the extensive deposition of enamel 

 on the columellar lip, which not infrequently extends to a considerable distance out- 

 side the aperture. Most of the species are littoral, and at low tide our New England 

 flats are covered with myriads of Nassa trimttata and N. obsoleta. Farther south a 



