MONOGRAPH OF AMERICAN SHIPWORMS. 19 



The center of the median portion is marked by a roughened area 

 which extends from the iimbones to the ventral margin, where the 

 usual strong knob is present. The auricle extends over the posterior 

 median portion and forms a narrow, thin, free shelf, with very little 

 of a cavity behind it. The auricle is marked by strong, curved lines 

 of growth. The pallets are spatulate, very short stalked and very 

 broad, the distal dark portion being decidedl}^ hollowed out, almost 

 suggesting a basal joint of BanMa. Of the animal we may say that 

 the siphons are of unequal thickness but almost of equal length. They 

 are tipped with numerous rose-colored spots. They extend about 

 half the length of the spatulate portion of the pallets, and are split 

 to the base of the spatulate portion. A broad collar in the shape of 

 a membrane surrounds the stalked portion of the pallets and extends 

 down over the rest of the animal for a length equal to the exposed part 

 of the siphons. 



The type, Cat. No. 341155, U.S.N.M., was collected in San Pablo 

 Bay, California. It measures: Height, 5.5 mm.; length, 6 mm.; 

 diameter, 7 mm. The pallets measure: Length, 5.5 mm., of which 

 2 mm. go to the stalk; width. 2 mm. 



TEREDO (TEREDO) NOVANGLIAE, new species. 

 >EW EXGLA>D SHIPMORM. 



Plate 21, fig. 3; plate 32. fig. 3. 



Shell subglobular, of medium size. Anterior half flesh colored, 

 the rest white. The extreme anterior portion of the anterior part 

 is marked by the usual sinus, which is covered by a smooth callus 

 that is reflected and appressed to the anterior portion of the ante- 

 rior part, its limit being a rather Avell marked line. From this 

 callus the dental ridges slope abruptly downward and then back- 

 ward in an even curve, spreading out fanshaped. At the posterior 

 extremity they are about as wide as the spaces that separate them. 

 These dental ridges slope abruptly on the dorsal side and very 

 gently on the ventral, the latter being about three times as long as 

 the former. Of these ridges, which are not eroded at the umbones 

 in the type, 27 are present. The free angle is extremely finely den- 

 ticulated. The anterior median portion is narrow and marked by 

 dental ridges which join those of the anterior part at a little more 

 than a right angle. These dental ridges are provided with very 

 strong denticles. The junction of the anterior and the anterior me- 

 dian part forms a slightly sinuous line. The middle median por- 

 tion forms a depressed groove in the center, both the anterior and 

 the posterior portion being concave. The entire portion is marked 

 by rough irregularly spaced threads. The posterior median portion 

 is about as wide as the anterior and middle combined, and is some- 



