34 pholadidj:. 



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, 

 but the 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 poste- 

 rior margin, not reflected, its inner face concave and 



Ly rod IIS cldorotica. i niii* xi i -i x^jiii 



broadly shelvmg over the deep cavity of the beaks ; 

 no callosity to beaks ; 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 bon}^, acorn-shaped nucleus. Diameters a])out 3 millimeters. 



From timbers of shi|)s that have cruised in the Pacific. 



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 Avhich have 

 no cups or transverse segments as in Xylotrya. The Ijurrows do 

 not run in the course of the grain of the plank, 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 thhi 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. 



Oenus XYJLOTKYA, Leach. 1830. 

 HiPHONAL pallets elongate, penniform. 



Xylotrya flmbriata. 



Shell subtrigonal, diameters about equal, striiu ou anterior triangle about thii-ty; 

 I)Osterior 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. 



Twedo hipalmulata, Thompson, Ann. and Mag. Nat. llist. (Oct. 1847). 

 Teredo /xdmuliita, Foruks and Hanl. Brit. Moll. i. 8(), ]>]. 2, tig.s. 9-11. — Sow kui-.y, 

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



