75 



slender transverse ribs, which become obsolete on the anterior sur- 

 face ; in the intercostal spaces, with rather coarse distant spiral 

 raised lines, whi{?h traverse the ribs only at their anterior extremities 

 on the last whorl : nucleus consisting of little more than one smooth 

 whorl, very oblique : spire with the outlines slio;htly convex : whorls 

 nine besides the nucleus, scarcely convex, with a well impressed su- 

 ture : aperture ovate, subacute above : labium slightly thickened : 

 umbilical region scarcely indented. 



Mean divergence about 12°; length of spire .125 inch; total 

 length .165 inch: breadth .045 inch. 



Chemnitzia reticulata. Shell moderately elongated : white : 

 with about twenty-six to thirty rather strong transverse ribs, which 

 become obsolete on the anterior surface ; with very coarse distant 

 spiral raised lines, decussating the ribs : nucleus consisting of a little 

 more than one smooth whorl, very oblique : spire with the outlines a 

 little convex ; whorls about seven besides the nucleus, slightly con- 

 vex, with a well impressed suture : aperture ovate, acute above : 

 labium scarcely thickened : umbilical region not indented. 



Mean divergence about 12°; length of spire .09 inch; total length 

 .125 inch; breadth .04 inch. 



Note on Pholas corticarla Soioh. By C. B. Adams, Feb. 1850. 



This species was discovered by me in the bark of a log, on the shore 

 of the Bay of Port Royal, near Kingston, Jamaica, in March, 1844. 

 Specimens were distributed with the Mss. name of P. rosea, sub- 

 sequently altered to P. corticaria. Some were sent to the British 

 Museum and to Mr. Cuming's collection, where they were seen by 

 Mr. Hanley, who affirmed them to be not distinct from a variety of P. 

 pusiUa Linn. In deference to his opinion, the description was sup- 

 pressed from my ' Synopsis' of nQW species from Jamaica. In Part 

 X of Sowb. Thes. Conch. (Dec. ?) 1849, a description of this species is 

 published for the first time, with the name of ' P corticaria Gray, 

 Mss.,' as being in the British Museum, without indication of habitat. 

 It is said that ' the specimens, having bored in floating mahogany, 

 have taken a reddish color.' This color was derived from the bark of 

 the tree. The shells did not penetrate the wood, and where they were 

 in contact with it, they were distorted, as if unable to penetrate it. 



