o4 PHOLADID^. 



ascendant, obtuse at point, with about forty diverging square ribs, 

 the interspaces finely barred ; marginal area of the claw very broad, 

 the ridges as broad as those of the anterior wing and coarsely barred, 

 Fi" 360 ^^^^ ^^^® interspaces very narrow ; at the junction of 



the two series is a deep diagonal groove towards 

 which they slope ; a sharp angle limits the anterior 

 area, followed by a barred groove ray, then a very 

 narrow posterior area with a lunate auricular projec- 

 tion, occupying about the middle third of the postc- 

 lior margin, not reflected, its inner face concave and 



Lyrodus cklorotica. i nil- ji i •, <* ,^ t -i 



broadly shelvmg over the deep cavity oi the beaks ; 

 no callosity to Ijcaks ; denticle slender, blade attached close to the 

 denticle, linear, somewhat granulate. Pallets paddle-shaped, the 

 stalk flexuous and very delicate, the blade half as long as the stalk, 

 lyre-shaped, the extreme two thirds covered with a dark crust which 

 has a projecting horn at each angle ; when the crust is detached there 

 is left a bony, acorn-shaped nucleus. Diameters about 3 millimeters. 



From timbers of ships that have cruised in the Pacihc. 



This species is remarkable for its minute size and globular form, 

 its large sculptured claw-area, and its peculiar pallets, to which there 

 is nothing similar among the species of true Teredo^ and which have 

 no cu})s or transverse segments as in Xijlotrya. The burrows do 

 not run in the course of the grain of the ])lank, but transversely, 

 and stand thickly side by side so as to resemble honeycomb, or the 

 organ coral, Tubipora musica; the tubes are lined by a thin gummy 

 or horny coat, and terminate in a concave calcareous disk with a 

 sort of transverse scar on its outer or convex face. I have not been 

 able to detect any transverse partitions. If on these accounts it 

 should be considered as entitled to generic distinction, it may be 

 denominated Lyrodus. 



Ociius XYI^OTKYA, Leach. 1830. 

 Siphon AL pallets elongate, penniform. 



Xylotrya flmbriata. 



Shell ^subtrigonal, diameters about equal, striic on anterior triangle about thirty; 

 posterior auricle large, sloping from the beak and descending much below the 

 anterior triangle, inner face fan-shaped, large, overhanging, concave, concen- 

 trically striate. Pallets oar-shaped, the blade as long as the handle. 



Teredo hipabnuhita, Thompson, Ann. and Mag. Nat. Hist. (Oct. 1847). 

 Teredo palmulata, Forbes and Hanl. Brit. Moll. i. 86, pi. 2, ligs. 9-11. — So\veki;y, 

 Illiist. Brit. Shells, pi. 1, fig. 6. 



