550 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



ridges, which are very finely denticulated at their free margin, 21 are 

 left in the type. A large number must have been eroded at the 

 umbone. The junction of the anterior part with the anterior mar- 

 gin of the median part forms a shallow curve. The anterior portion 

 of the median part is marked by slender denticulated ridges which 

 arc separated by deep narrow grooves. Of these ridges 17 are pres- 

 ent in a straight line across the anterior median part from the basal 

 margin of the anterior part. The individual denticles of these ridges 

 bear doubly denticulated cusps, the anterior denticle being about 

 twice as large as the posterior. The middle portion of the median 

 part is moderately broad, the anterior half of which is slightly convex, 

 while the posterior half is slightly concave; both are crossed by the 

 continuation of the dental ridges of the anterior portion which here 

 take a decided turn, become much enfeebled and edentulous. The 

 posterior portion of the median part is about as wide as the ante- 

 rior and middle portion combined. It passes in a gentle depression 

 directly into the posterior auricle and bears a continuation of the 

 fluted wavy sculpture of this part. The posterior auricle is mod- 

 erately large and poorly differentiated from the posterior portion of 

 the median part. It is marked by rather regularly disposed rib- 

 like raised wavy elements which are parallel with its ventral margin 

 in disposition. Interior bluish-white. The anterior and median 

 portion are joined in a distinct raised thread; the middle median 

 portion is slightly roughened and terminates ventrally in a strong 

 rounded knob; the auricle fuses with the posterior median portion 

 without any demarkation or shelving; it is for that reason that I am 

 placing this shell in the subgenus Psiloteredo , with a question mark; 

 the umbones are strong and from their ventral margin an oblique 

 somewhat irregular blade extends parallel with the middle area 

 through four-fifths the length of the shell. The pallets of this species 

 have not been found, and it will require their presence before we can 

 give a fixed systematic status to this species. 



The type (Cat. No. 312931, U.S.N.M.) was collected by the United 

 States Bureau of Fisheries Steamer Albatross Philippine Expedition, 

 in a piece of wood dredged at station 5294 off Escarceo Point, north- 

 ern Mindoro, in 244 fathoms on sand and pebbly bottom; bottom 

 temperature, 48.4°. It measures: Height, 2 mm.; length, 2.1 mm.; 

 diameter, 2 mm. Another specimen (Cat. No. 365932) comes from 

 station 5294 of Escarceo Point, Northern Mindoro, in 244 fathoms 

 on sand and pebbles; bottom temperature, 48.4°. 



Genus EOTEREDO Bartsch 



1923. Eoteredo Bautsch, Proc. Biol. Soc. Wash., vol. 36, p. 98. 



Blade not projecting from the under side of the inside of the um- 

 bones, but attached to the middle of the broad shelf that constitutes 



