MANUAL OF THE MOLLTJSCA. 



On the other hand, Mr. Bowerbank has a curious example of 

 "instinct at fault," in the fossil spine of a sea-urchin, which 

 appears to have been drilled by a carnivorous gasteropod ! 



We have spoken of shell-fish as articles of food, but they have 

 other uses, even to man ; they are the toys of children, who hear 

 in them the roaring of the sea; they are the pride of "collectors" 

 whose wealth is in a cone or " wen tie-trap ;"* and they are 

 the ornaments of barbarous tribes. The Friendly-islander wears 

 the orange-cowry as a mark of chieftanship (Stutchbury), and 

 the New Zealander polishes the elenckus into an ornament more 

 brilliant than the " pearl ear-drop" of classical or modern times. 

 (Clarke.) One of the most beautiful substances in nature is the 

 shell-opal, formed of the remains of the ammonite. The forms 

 and colours of shells (as of all other natural objects), answer some 

 particular purpose, or obey some general law ; but besides this, 

 there is much that seems specially intended for our study, and 

 calculated to call forth enlightened admiration. Thus the tints 

 of many shells are concealed during life by a dull external coat, 

 and the pearly halls of the nautilus are seen by no other eyes 

 than ours. Or descending to mere "utility," how many tracts 

 of coast are destitute of limestone, but abound in shell-banks 

 which may be burned into lime ; or in shell-sand, for the use of 

 farmers.f 



* The extravagant prices that have been given for rare shells, are less to 

 be regretted, because they have induced voyagers to collect. Mere shell-col- 

 lecting, however, is no more scientific than pigeon-fancying, or the study of 

 old china. For educational purposes the best shells are the types of genera, 

 or species which illustrate particular points of structure ; and, fortunately for 

 students, the prices are much diminished of late years. A Carinaria once 

 " worth 100 guineas" (Sowerby) is now worth Is. only; a Wentle-trap which 

 fetched 40 guineas in 1 701' (Rump hius) was worth only 20 guineas in 1753, 

 and may now be had for 5s. I The Conus gloria-mans has fetched 50 more 

 than once, and Cyprcea umbilicata has been sold for 30 this year, 1850. 



f Shell-sand is only beneficial on peaty soils, or heavy clay land. It 

 sometimes hardens into limestone, as on the coast of Devon ; and at Guada- 

 loupe, where it contains litoral shells and human skeletons of recent date. 



