194 LECTURES ON MOLLUSCA. 



beautiful group Myurella has the band nodulous. Euryta is a curious 

 group in which the spire is shorter, and the canal so twisted that the 

 pillar appears pierced. The form of these shells offers a transition to 

 Buccinum; while a few other species present the aspect of Cerithium. 



We have now passed under review all the Gasteropods which are 

 known to possess a retractile proboscis. It is not certain that all of 

 these are strictly carnivorous ; and it is almost certain that some tribes 

 which have a permanently elongated muzzle are not vegetarians. 

 Between these two great leading divisions of the comb-gilled crawlers, 

 there is a somewhat anomalous group, the true position of which is not 

 'yet ascertained. It is strange, (and not, perhaps, very creditable to 

 naturalists and collectors,) that Cowries have been among the com- 

 monest shells from the earliest times ; abound not only in species, but 

 in individuals ; form a regular staple of trade ; are found in all warm 

 seas ; and yet a reliable account of the anatomy of the animal is still a 

 desideratum. Scientific observers have frequently given accounts of 

 them, and the creatures are figured in many of the great voyages; and 

 yet Dr. Gray asserts that it has a short muzzle, grouping it with the 

 land and sea Periwinkles, while the whole army of ordinary naturalists 

 declare that it has the retractile proboscis of the Whelks. At my re- 

 quest, Dr. Stimpson examined the animal of the large and typical 

 Cyprcea testudinaria, which had been brought home by the United 

 States Exploring Expedition ; and to our surprise it did not accord 

 with either the one or the other type, but, on the contrary, furnished 

 us with an example of a retractile muzzle. The snout, contracted in 

 alcohol, was about half the length of the shell. Instead of being 

 drawn in from the base, as in Whelks, it was drawn in from the tip ; 

 The tongue-ribbon was coiled up in a cavity near the stomach. 

 Probably the end of the muzzle protruding in front of the tentacles 

 has been mistaken for the ordinary rostrum. 



The teeth of Cyprce-a helvola are very like those of the land and sea 

 Periwinkles ; but those of Trivia europcea have no small resemblance 

 to those of Natica. The teeth of Ovulum are altogether peculiar; 

 whether, therefore, the egg shells are rightly classed with the Cowries, 

 remains to be seen. 



Family Cypr^id^;. {Cowries.) 



The Cowry shells, when adult, are nearly globular, not showing any 

 spire, with a narrow mouth, toothed on each side, nearly in the middle 

 of the base; with a deep notch at each end. They are almost always 

 smooth and polished. When young, however, they present a very 

 different shape; being then very thin, with an open mouth, sharp lip, 

 and short spire. At that period they have the general aspect of Olives 

 without the plaits; and, as they never display the same shape or pat- 

 tern that they do in mature life, they have sometimes been described 

 as differ en t species. The adolescent Cowry curls-round the sharp edge 

 of his mouth, and then begins to make teeth on each of the lips. At 

 the same time, the mantle spreads out, forming two great flaps, one of 

 which envelops each side of the shell, and deposits layer over layer of 



