32 OLIVID-E. 



Genus 11. MIC AN A. 



Shell ovate or obconic ; spire conical, callous ; upper sutural 

 groove obliterated ; aperture ovate ; inner lip thickened, ex- 

 panded; pillar with two small grooves in front; anterior belt 

 narrow, single. Animal ? Operculum half-ovate, horny. 



1. MlCANA NANA. B.M. 



Voluta nitidula, Soland. 3ISS. 



Dillw. R. S. 521. 

 V. utriculus, var., Gmelin, E. 31. t. 363. f. 4. 

 Oliva nana, Lamk. Hist. no. 60 ; Ann. no. 57 ; E. 31. t. 363. f. 3. 



Duclos, OJiv. t. 25. f. 5-8 (operc. A, B). 



Reeve, C. I. t. 23. f. 66. 

 Voluta ispidula, var., Horn. 

 Micana nana, Gray, Proc. Zoot. Soc. 1858, 57. 

 Oliva micans, Desh. 

 Voluta micans, Soland. 3ISS. 



Dilho. R. S. 521. 

 Oliva millepunctata, Duclos, Oliv. t. 25. f. 1-4. 



Reeve, C. I. t. 28. f. 87. 

 Oliva oryza, Duehs, Oliv. t. 1. f. 9, 10. 

 Voluta oryza, Dilhc. R. S. 522. 

 01iva rufiiasciata, Reeve, C. I. t. 28. f. 88. 

 Hah. West Indies. 



The Olives are known from the Ancillaria by the sutural 

 groove on the spire ; but in some species which have a very 

 distinct groove, it becomes obliterated and entirely hidden by 

 a callous deposit on the spire, especially on the upper whorls. 



Duclos regarded this deposition of shelly matter on the spire 

 as a good character for the separation of the species, and I was 

 induced to follow his opinion, and have, in the ' Proceedings of 

 the Zoological Society,' given to his section a distinct generic 

 name. I believe that it is a very permanent character in some 

 species, but at the same time it is certainly not permanent in 

 others : thus, in the British Museum there are four specimens 

 of Oliva micstelina ? received at the same time from China, two of 

 which have the groove quite open to the tip, one with it partly 

 closed, and the other with the grooves on the upper whorls 

 quite obliterated and covered with a thick callosity ; this latter 

 specimen is considered by M. Duclos as another species and 

 referred to a different section. In the same manner I am induced 

 to believe, from a specimen in my cabinet, that his Oliva irisans 

 is only a variety of Oliva ispidula with the spire covered with 

 a callous deposit ; and I have observed that several of the speci- 



- 



