i^:eivie^w^. 



THE GENUS LATIRUS (MONTFORT). By 



J. Cosmo Mei.vim,, M.A., F.L.S. (Manchester, 

 1891).* 



WF^ have pleasure in noticing this most 

 interesting and useful little monograph 

 on the genus Latirus, written with a lucidity 

 and elegance that characterise all the writings 

 of Mr. Melvill. In the space of 48 pages 

 the author reviews the (i.) Early History and 

 Classification ; (ii.) General Characteristics ; 

 (iii.) FLxisting Monograi)hs ; (iv.) Derivation 

 of Name; (v.) Fossil Forms; (\i.) Classifi- 

 cation and Dentition, &:c., «l'r. Mr. Melvill 

 suggests as a possible derivation of the 

 word Latifus, the word laterHius, " of or 

 belonging to a brick, from the warm, sun- 

 dried brick colour of some species, especially 

 the type, Z. GiMii//its (Gmelin) " — spelt in 

 all the editions of Woodward's Manual, in 

 both letter-press and plate-references, GJl- 

 buliis. The dentition seems to claim a 

 prominent place in the history of this genus 

 and its allies. In fact, there is an unusual 

 dependence upon it for the purpose of both 

 generic and specific distinction. " Mr. Cooke 



' An Historic.il Account of the genus Latirin (Moiitfort) and 

 its dependencies, with descriptions of Eleven new species, and 

 a Catalogue of Latirus and Peristeniia, hy James Cosmo 

 Melvill, M.A., F.L.S. (Mem. and Pro. of the Manchester Lit. 

 and Phil. Soc. ^Linchester. 1891). 



t Mr. Melvill gives a list of 40 known species. 



No. 4. Dec., 1891. 



considers the dentition sufficiently distinct 

 in Peristeniia to keep that genus distinct 

 from Laiinis ; but he has examined only 

 four species of the genus." f We agree 

 with Mr. Melvill that " it is very difticult 

 to draw a hard and fast line, unless 

 the odentophore of each is known and 

 examined." While recognising the im])Ort- 

 ance of the dentition as a valuable aid in 

 classifying, to make it the basis of a classi- 

 fication is about as absurd as the old idea 

 of relying entirely upon the shell. Is there 

 no account of the anatomy of any of 

 these genera^ ? Speaking of the irridescent 

 epidermis in some species, Mr. Melvill 

 ^vi-ites :— " In three or four species the 

 epidermis, when wetted or oiled, shows 

 prismatic reflections. 1 do not know this 

 peculiarity in any other genus, nor does 

 it exist in many La/iri. It is most 

 conspicuous in the still uncommon Z. 

 prismatiais of Martyn, who, under its old 

 title Ihiciinuni prisniaiictim, figured it in his 

 'Univ. Conch.,"" vol. u, p- 2 . . • "I 

 have often noticed, in deep tidal ponds 

 around our coasts, and likewise in those 

 of other countries, certain marine ;\lg9e, 

 appearing beautifully prismatic in the water, 

 steel-blue or sea-green being the prominent 

 reflections, the effect of which vanishes, 



