RISSOA. 131 



R. SOLUTA. 



Like pulcherrima, but less globose, not variegated, and with 

 excessively minute spiral striulae. 



Plate LXXV. tig. 3, 4. 



Rissoa soliUa, Philippi, Moll. Sicil. vol. ii. p. 130, pi. 23, f. 18 .^ ? — Jeffreys, 

 Ann. Nat. Hist. voL xx. p. 16. 



We cannot venture to follow Mr. Jeffreys^ identification 

 of our native species with the Sicilian one, since not only 

 is the former very different from the shell presented to us 

 by Dr. Philippi, but the figure of the latter represents a 

 narrower and more produced shell, with a more pointed 

 apex, and a more produced spire. The last whorl is 

 stated, likewise, to be almost disconnected, and the surface 

 to be perfectly smooth. We retain provisionally the name, 

 since in the event of the original soluta not proving a valid 

 species (and we are in doubt about its claims) the present 

 shell may assume the vacated epithet. 



The shell is excessively minute, extremely thin, semi- 

 transparent, highly lustrous, and of an uniform clear pale 

 fulvous yellow. The shape of the few larger specimens 

 we have seen (those with four volutions) is oval-conoid ; but 

 the individuals more usually to be met with in cabinets 

 (those with three and a half turns) are subglobular-conic ; 

 the surface is smooth to the eye, and even so to a common 

 lens, but under a glass of higher power is perceived to be 

 regularly aud densely striated in a spiral direction, which 

 sculpture is more apparent upon the base than elsewhere. 

 The whorls, which rise rather abruptly from the simple 

 but profound sutural line, that divides them from each 

 other, are rounded, yet are slightly shouldered above; 

 their longitudinal increase is rather rapid. The spire is 



