212 Bartsch — A New Shipworm from the Unit"! States. 



Interior. — The anterior projection extends prominently over the central 

 part, at its posterior edge, forming a strong, free lamella. The part ante- 

 rior tu the junction with the central area is marked by many subequal 

 and subequally spaced, slender threads which coincide with the incre- 

 mental lines. The central part is smooth, except the middle portion, 

 which is decidedly roughened and hears a prominent snhcylindric knob 

 at the ventral tip. The fusion of the central area and the posterior pro- 

 jection is marked by a thickened suture. The posterior projection is 

 smooth, but permits the exterior sculpture to he seen through its semi- 

 transparent mass. The blade which extends obliquely from the thickened 

 umbo is rather broad, thin and sickle-shaped. 



Pallets plumose, with a slender stalk which is almost as long as the 

 blade. Junction of stalk and blade well marked; the first element of the 

 blade appears as if the stalk were sunk in it. The blade itself is lanceo- 

 late, and is formed by a series of depressed cone-in-cone structures which 

 have their bases partly free. The entire blade appears to he covered by 

 a thin, horny film which bridges over the gap between the free base of 

 one cone to the body of the next. The outer surface is well rounded; the 

 free edge of the cone forms a decidedly curved outline, giving the blade 

 the aspect of an ear of rye. The inner surface of the blade i^ almost flat- 

 tened, and the elements are less deeply curved than on the outside. 

 There are seventeen ( 17) joints to the blade of the type. 



The type. Cat. No. 27,415 U. S. X. M., was collected in Norfolk Har- 

 bor, Va., and measures: altitude 8.6 mm., length 8.5 mm., diameter 9.2 

 mm., length of the blade of pallet 0.7 nun., greatest diameter of blade 2.0 

 nun., length of stalk 7.7 mm. The National .Museum has specimens of 

 this species from the following localities: 



Virginia: Norfolk Harbor, Newport News. Hampton Roads, Smith's 

 Point, Chesapeake Bay. South Carolina : Charleston. Florida: Cedar 

 Keys, St. Andrews, Pensacola, Pascagoula Bay. Texas: Galveston. 

 Louisiana: Chandeleur Islands, Cameron. South Atlantic 



