smith: on the genus scutus. 255 



unguis (== corriigatus Reeve) by Tapparone-Canefri in the ' Mala- 

 cologia del Viaggio della Magenta.' According to Hogg's figures 

 the odontophore has a broad central tooth with four much 

 narrower ones on each side of it, and adjacent to these are the 

 pleurse, the innermost one being strong with two stout terminal 

 denticles of which the inner is much the more formidable. The 

 rest of them are very fine in comparison and hooked at the ends. 

 Although the same detail is indifferently portrayed in the ' Astro- 

 labe,' pi. 69, f 10, yet MM. Quoy and Gaimard assert in the 

 text, vol. iii, p. 317, " crochets sur sept rangees." 



I myself have examined the odontophores of several 

 specimens of Scutus unguis^ S. ainbiguus and 6*. anatinus, and 

 with the exception of size I can perceive no appreciable differ- 

 ences. I therefore conclude that the figure given by Tapparone- 

 Canefri is not quite accurate which represents the arrangement 

 thus : central tooth very large, with seven smaller ones on each 

 side which gradually lessen in size outwardly ; beyond these a 

 very strong pointed prong-like tooth, and again without this a 

 border of a fringe-like aspect. 



The color of the animal in this genus is generally black or 

 nearly so, but is subject to variation. Dr. Tapparone-Canefri 

 describes a Japanese specimen of Scutus unguis (var. corrugatus 

 Reeve) as white with the sides of the foot blotched with black. 

 Another from the Red Sea, which I believe most probably belongs 

 to the same species, is said by Riippel to be black above with the 

 foot grey beneath. Another in the British Museum from Zanzibar is 

 of a uniform pinkish-buff tinge, and a second also in the 

 museum and likewise of this species is of a whitish or yellowish 

 color blotched with dark grey upon the mantle and sides of the 

 foot which is uniform buff below. 



What specific importance to attach to these differences of 

 color it is difficult to determine, for as is well known alcoholic 

 specimens of mollusca give but a faint idea of the splendid colors 



