Z7^ 



Mr. Cosmo Melvill on the 



Latirus are distinct from Peristernia in many particulars, 

 Mr. Cooke, to whom I am much indebted, has lent me some 

 very beautiful magnified photographs of the dentition of 

 two species — Fasciolaria trapezium (Lam.) and Latirus 

 ceratus (Wood). The dentition appears to vary as follows 

 between the three genera : — 



Fasciolaria (Lam.). 



Latirus* (Mtft.). 



Peristernia (Morch). 



Central tooth tricuspi- 



Central tooth tricuspi- 



Central tooth tricuspi- 



date, close together. 



date. 



date. 



Lateral denticles, about 



Lateral denticles about 



Lateral denticles irregu- 



21 in number, lon^ 



lo, broader at base. 



lar in size, about 8 



comb - like, equal 



not so long as in Fas- 



large teeth, 5 small 



length to base. 



ciolaria. 



ones. 



Mr. Cooke considers the dentition sufficiently distinct in 

 Peristernia to keep that genus distinct from Latirus ; but 

 he has examined only four species of the genus, and it is 

 very difficult to draw a hard and fast line, unless the 

 odontophore of each is known and examined. 



A small shell, Taron dt^dius (Hutton), from New Zealand, 

 of which the Rev. A. H. Cooke very kindly forwarded me 

 specimens, has been discovered by the dentition to belong 

 to the LatiridcB. The shell is not unlike a small Cominella^ 

 fusiform, with short canal, columella smooth, lip simple, 

 ornamented with transverse ribs, often semi-nodulous. 

 Length 15 m. Breadth 7 m. 



Apart from the lingual riband, the general aspect of the 

 Animal of Latirics and Peristernia resembles the Muricidce. 

 The head is somewhat broader, eyes less protuberant, foot 

 rather shorter than in typical Murex. The operculum is 

 distinct, all the Fasciolariince possessing unguiform opercula, 

 with the nucleus apical. When on the coral reefs of the 

 Gulf of Mexico, in 1872, where I noticed L. cingulifera 



* With Aptyxis (Troschel), Taron (Hutton), Boreofusus (Sars). 



