A 



NASSA. 17 



(ii'iuis NASSA. I. nil. 

 II. iind A. Ad.'ims in their "Greneni of Recent Molinscn"' ii;ive 

 ennmemted 210 species of X:issa; Reeve's Monograph in the 

 "Conchologia leonica" contains 182 accej^te;! species and 18 

 synonyms, =: 11)5 names in all. The present mono<>rai)h includes 

 595 specific names, of which 131 only are accepted as s;ood 

 species, 304 are releoated to the synonymy of these, and 100 arc 

 undetermined for want of illustrations or specimens. The dis- 

 tribution of the genus is world-wide, except that no specimens 

 exist in the icy seas near the poles — where they api)ear to be 

 replaced by the Buccinums. They occur principally- in the waters 

 of tropical and subtropical latitudes. 



The fossil species are few in number, commencino- with the 

 Eocene formation. For some of the American fossils Mr. T. A. 

 Conrad has proposed distinct generic names, but their separation 

 from Nassa is scarcel}^ advisal)le. 



The animal of Nassa has a broad head, and a foot ciuadrately 

 expanded in front, with the corners often pointed, whilst behind 

 it bifurcates and is prolonged frequently into two sul)ulate tails. 

 The operculum is usually serrate on the margin but is sometimes 

 plain. The Nassjie are veiy active, and not at all shy when kept 

 in confinement. They may be occasional!}^ seen floating with 

 the foot upwards. They are predaceous, feeding on other mol- 

 lusks, the shells of which they bore. I have frequently seen the 

 shells of the American species themselves bored, the hole being 

 of such a size as to suggest cannibalism. Perhaps the avenger 

 of their misdeeds is a beautiful and very active hermit eral) 

 which disports itself in the Nassa's shell, immense multitudes 

 being seen at low tide in the water near the shore line. Whether 

 begged, borrowed, stolen, or lawfully captured by the red right 

 claw, it is certain that, at Atlantic City, New Jersey, the hermit 

 inhabits avast majority of the specimens of Nassa occurring to 

 the collector. Although most of the species are littoral, a few 

 have been collected at considerable depths ; the undescribed N. 

 hrychia^ Watson, was dredged at (i20 fathoms by the "Challenger 

 Expedition." S6me of them have been observed to spring- 

 up and throw themselves over oil being suddenly disturbed. 

 Usually they glide along the surfiice of the mud, leaving a track 

 indicating their line of march, at the end of which is a small 



