172 COOKE: ON THE GENUS CUMA. 



gap in the distribution occurs, unbridged by the occurrence of 

 any species. For, broadly speaking, the Malay peninsula is the 

 metropolis of carinifera and gradata, Western tropical America 

 of kiosquiformis and tectum. If however the genus be restricted as 

 here proposed, we have one more well marked example of what 

 I may call 'modified Purpuras^ pecidia?- to the W. coast of America. 

 Cuma, Monoceros and Concholepas will then rank together, as 

 characteristic of this coast, and of this coast only, the columellar 

 tooth in Cuma being paralleled by the labial tooth in Monoceros. 



The exact limits of the distribution of Cuma tectum are not 

 known. Its metropolis appears to be Panama ; where I have 

 collected it in large numbers at low water mark, neap tides, in 

 clefts of rocks. It does not extend northwards as far as Mazatlan; 

 or (apparently) southwards as far as Guayaquil, and it does not 

 occur at the Galapagos. 



A word in conclusion with regard to nomenclature. The 

 Genus Cuma., as constituted by Humphrey in 1797 (Mus. 

 Calonn., p. 35, genus 60), is an omnium gatherum of fourteen 

 species, from which this at most can be learned, that it includes 

 two species of Fasciolaria {tulipa and trapezium) and one of 

 Pyrula (inorio). To say that Humphrey constituted the genus 

 is perhaps to pay him too great a compliment, as his ' genera ' 

 are merely unscientific groupings of species under popular 

 names, for sale purposes. 



Swainson, in 1840 (Malac, pp. 73, 87, 307), first took the 

 name up, making Cuma a subdivision of the Fyrulince, and 

 taking as the type, and apparently as the only species, sulcata 

 Swains. {=tectum Wood). He regarded Cu7na as a passage 

 between Pyrula and Fusus, giving the following description ; 

 Shell subfusiform ; spire and base equal in length ; inner lip 

 with a central fold. 



Gray (P. Z. S., 1847) placed Ctwia Swains, in his section b 

 of the Muricidce, between Rapana and Latirus. 



It follows therefore that for Cuma Humphr. must be sub- 

 stituted Cuma Swains., although the latter author did not 

 correctly estimate the position of the genus. 



J.C, v., April, 1887. 



