THE NAUTILUS. 77 



With each of these are a sufficient number of species to make the 

 generic distinctions at once ap})arent, thus enabling the student to 

 locate in the general collection any genus he might wish to exam- 

 ine. 



Following this group are the genera with their full complement 

 of species, the bulk of the latter represented by specimens, the 

 remainder by figures or models. 



First in line are the Cephalopods, which as your readers know, 

 comprise the highest class of the Mollusca. 



Only a few of these produce shells that are wholly external. A 

 fine display, however, of those belonging to the Nautilus and Argon- 

 auta are to be seen, together with many rare models of shell-less spe- 

 cies. 



Near these are several trays of frail glass-like shells belonging to 

 the class Pteropoda. Of this class quite a number of genera are rep- 

 resented making a very dainty and delicate group. 



Next in order comes the Marine Gastropods, a class containing 

 a far greater number of genera than either of the others named. In- 

 cluded in these are the Murices, Tritons, Purpura, Volutes, Fusus, 

 Mitra, Marginella, Olives, Cones and Cypraea. 



In all of these are rare and costly specimens, while some of them 

 show an almost complete series of the species. 



This is especially so as regards the Cones, Olives and Cypraea, the 

 last being the largest and finest collection of its kind in the United 

 States save that belonging to John H. Campbell Esq. of Philadel- 

 phia, which is indeed worth a long journey to see. Exquisite speci- 

 mens are also plentiful in the other genera mentioned. Passing 

 from these the visitor will meet with many series of genera belong- 

 ing to the same class. Though less prominent, perhaps, than those left 

 behind, they are in some respects quite as interesting. 



Among them is the genus Cerithium, a group of wax-like shells, 

 whose "quaint and curious" forms make them delightfully attrac- 

 tive. Here too are the Littorina, the Turbo, Trochus, Phasianella 

 and many others including the genus Haliotis which in beauty, 

 number of species and size of specimens, can faii'ly claim the atten- 

 tion of all lovers of Nature's handiwork. 



Near to these are the Patella, Bulla and Chitons, all of which 

 are worthy of attention, though among the last of the Marine Uni- 

 valves. 



