THE MUSEUM. 



A Monthly Magazine Devoted to Research' in Natural Science. 

 Vol. II. 



ALBION, N. Y., DEC. 15, 1895. 



No. 2 



SHOWY SEA SHELLS. 



Interesting Notes About Shells 



That are Easerly Sought for 



by Collectors. 



{Continued froiii last number. \ 



In this paper we will review some of 

 the Cassis and Purpura. 



In the genus Cassis the shell is oval, 

 convex and the spire is not of consid- 

 erable height. The longitudinal open- 

 ing is narrow, terminating in front in 

 a short channel, which becomes sud- 

 denly erect toward the back of the 

 shell as in cassio g/aiica [Fig. 22] a 

 fine shell from the Moluccas, The 

 columella is folded or toothed trans- 

 versely, as in Cassis rufa [Fig 23], 

 the right edge thick, furnished with a 

 sort of pad externally, and dentate 

 within. This shell is from the Indian 

 ocean, and is of a fine purple color, 

 varied with black above, the edges of 

 the opening being of a coral red color, 

 the teeth alone being white. 



The head of the animal is large and 

 thick, furnished with two conical elon- 

 gated tentacles, at the base of which 

 are eyes. The mantle is ranged out- 

 side the shell, falling back upon the 

 edges of the opening and terminating 

 at its anterior extremity in a long cylin- 

 drical channel, cloven in front, and 

 passing by a hollow at the base into 

 the branchial cavity. The foot is 

 large and furnished with a horny oper- 

 culum. 



The animals keep near the shore, in 

 shallow water. They walk slowly and 

 often sink themselves into the sar)d. 



where they prey upon small bivalves. 

 There are not very many species, but 

 specimens from the Indian Ocean are 

 often large and beautifully marked. 



The shells of the less marked spe- 

 cies are frequenly used in India as lime 

 for making mortar, under the name 

 of Chunam. 



Our space only permits us to men- 

 tion, among the more curious species, 

 Cassis canaliculata (Fig. 24] and the 

 curious Casis Zebra (Lam), or Zebra- 

 marked Casque [Fig. 25]. 



The Purpuras have a classical name 

 and history, having furnished the Greeks 

 and Romans with the brilliant purple 

 coloring matter which was reserved for 

 the mantles of patricians and princes. 

 The genus Purpura is characterized as 

 possessing an oval shell, thick pointed 

 with short conical spiral, as in Purpura 

 lapellus [Fig. 26]. In some it is tu- 

 bercular or angular, the last turn of 

 the spiral being larger than all the 

 others put together. The opening is 

 dilated, terminating at its lower ex- 

 tremety in an oblique notch. The 

 columellar edge is smooth, often ter- 

 minating in a point; the right edge of- 

 ten digitate, thick internally, and fold- 

 ed or rippled. 



The animal presents a large head, 

 with two swollen conical tentacles, 

 close together and bearing an eye to- 

 wards the middle of their external side. 

 Its foot is large, bilobate in front, with 

 a semicircular horny operculum. 



The species of Purpura inhabit the 

 clefts of rocks in marine regions cov- 



