34 BULLETIN 122, UNITED STATES NATIONAL MUSEUM. 



stalk. To this attaches a solid portion which has two strong wings 

 passing up on the outside on either side. The median portion of the 

 pallet is depressed and naillike, and resembles verj^ much a finger 

 nail in its nail bed, there being a slight pocket at the basal margin. 

 The nail portion itself is marked by strong concentric rough lines. 

 A similar type of sculpture also charactesizes the edges of the lateral 

 areas of the basal portion of the blade. The inside of the blade is 

 smooth, and shows a rib running through its center very much as if 

 the stalk portion extended toward the tip through the pallet. 



Cat. No. 345349, U.S.N.M., contains three valves and two pallets 

 of this species collected by Sanderson Smith in New England. The 

 specimen figured measures: Height, 9.8 mm.; length, 9.7 mm.; diam- 

 eter, 9.9 mm. The pallet measures: Length, 9.9 mm., of which 2.2 

 mm. go to the stalk ; diameter of blade, 4,7 mm. 



This is the American analogue of the European Teredo {Tere- 

 dora) malleolus Turton, from which it is easily distinguished by its 

 having the median portion much wider than that form, and the auri- 

 cle comparatively much smaller and much less strongly sculptured. 



TEREDO (TEREDORA) PANAMENSIS, new species. 

 PANAMA SHIPWOBM. 



Plate 27, fig. 3 and 4 ; plate 35, fig. 2. 



Shell very short, with the median part extremely elongated ; white, 

 covered with a brown periostracum, except at the posterior border. 

 The anterior portion has the usual sinus, but very shallow in this 

 case. This is covered with a callus which is reflected over the outside, 

 where it extends over the dark periostracum for some little distance. 

 The dental ridges that radiate from under this callus bend down- 

 ward first and then in a gentle, even curve backward. There are only 

 nine of these present in the type. They are extremely distantly 

 placed, and stand out as strong lamellae, finely denticulated at the 

 free border, the margins of the denticulations extending down on the 

 sides of the dental ridges. The spaces separating the dental ridges 

 are marked by lines of growth, crossed at right angles by microscopic 

 striations. The median area is very narrow arid very long and bears 

 at the anterior margin a small number of dental ridges, which join 

 those of the anterior area in a little more than a right angle. These 

 dental ridges are marked by strong tubercles. The middle median 

 portion is slightly concave and marked by lines of growth only, while 

 the posterior median portion is extremely narrow and marked by 

 lines of growth only. The posterior area forms a very narrow auricle 

 which really appears as a partly uj)turned portion of the posterior 

 median area. This is marked by lines of growth only. The interior 

 is bluish white. The junction of the anterior with the median portion 



