38 BULLETIN 122, UNITED STATES NATIONAL MUSEUM. 



umbonal knob is strong, from the inner surface of which a slender 

 bhxde projects, which is about half the length of the shell. The pal- 

 lets are spoon-shaped, short stalked, and broadly expanded, and 

 show a slightly gouged out area, marked with concentric lines on 

 the outside. The inside shows the extension of the stalk up through 

 the mass of the pallet. 



Stimpson's type came from a pine buoy used to indicate the posi- 

 tion of the lobster pots of fishermen at Lynn and Marblehead, 

 Massachusetts. 



The specimen described and figured is one of a lot, Cat. No. 33630, 

 U.S.N.M., taken from United States Bureau of Fisheries Station 

 995 off Marthas Vineyard in 1881. 



le measures: Height, 8 mm.; length, 8 mm.; diameter, 8 mm. 

 The pallets measure : Length, 5.3 mm., of which 1.2 mm. go to the 

 stalk; diameter, 2.7 mm. 



This is the big-eared shipworm of the Northeast coast, which has 

 undoubtedly been listed by many authors as Teredo niegotara Han- 

 ley, which is European, from which it differs by its smaller size, 

 proportionately larger auricles, and by the differently shaped pallets. 

 In Teredo viegotara Hanley they are much more slender and elongate. 

 We have it from many stations ranging from Georges Bank and 

 Casco Bay south to Rhode Island. 



TEREDO (PSILOTEREDO) STIMPSONI, new species. 

 STIMPSON SHIPWOBM. 



Plate 28, fig. 3 ; plate 35, fig. 3. 



Shell large, yellowish white, subglobular, the anterior area with a 

 deeply incised narrow sinus, which is marked by a reflected callus 

 that is differentiated from the rest of the shell by an impressed 

 groove. From this callus the dental ridges radiate, taking first a 

 sudden downward course, then spreading out in a somewhat fan- 

 shaped, even-curved course. The dental ridges are separated at their 

 posterior termination by a space a trifle \a ider than the width of the 

 ridges. They slope a little more abruptly anteriorly than posteriorly 

 and are denticulated on their free margin. Sixty-four of them occur 

 in the type. The anterior median portion is very broad and is 

 marked by strong dental ridges, which are separated by well- 

 impressed grooves. These dental ridges join the anterior part at 

 almost a right angle. The middle median part forms a slightly 

 depressed groove, crossed by rather prominent cords and between 

 these finer threads. The posterior median area is about as wide as 

 the anterior and median combined, and is marked by the continu- 

 ations of the coarser threads that cross the median area, and also by 

 fine lines. The posterior area forms a very narrow inconspicuous 



