SHIPWORMS OF THE PHILIPPINE ISLANDS BARTSCH 535 



in an even curve backward. Forty-four of these ridges are present 

 in the type, but this is by no means the entire number, for the early 

 ones are completely eroded at the umbone. The ridges slope a little 

 more abruptly dorsally than ventrally, and are exceedingly finely 

 denticulated at the free margin. The anterior median area is very 

 broad; in fact in the type, which is the only specimen available, it 

 constitutes the entire median area. This, however, may be due to 

 erosion. The dental ridges of this part are almost twice as wide as 

 those on the anterior area. There are 40 in a line parallel to 

 the ventral margin of the anterior part. These ridges are strongly 

 denticulated. Posterior to the denticulated median portion the 

 shell slopes abruptly down into a very narrow shoulder, beyond 

 which only a very slender auricle projects. The middle and poste- 

 rior median part are apparently absent. Should this prove to be the 

 usual state of affairs, and not merely due to erosion, it will be neces- 

 sary to transfer this animal to a new genus. Interior bluish white. 

 Suture of the anterior and anterior median portion marked by a 

 raised cord. The posterior border of the median part is thickened 

 and bears the knob at its ventral margin. A very slender auricle is 

 present, which partly glazes over the middle part, forming the 

 merest indication of a shelf almost resembling Psiloteredo in its 

 reduction. A narrow irregular slender blade extends two-thirds of 

 the way from the umbone to the ventral margin of the shell. The 

 pallets are slender with a very slender stalk. The membrane on the 

 outside of the evenly rounded segments is finely fimbriated. The 

 inner border appears to be free of fimbriations and is also evenly 

 curved. 



The type (Cat. No. 310970, U.S.N. M.) was obtained by the United 

 States Bureau of Fisheries Steamer Albatross Philippine Expedition, at 

 station 5243, in 218 fathoms in a piece of wood taken from gray mud 

 bottom, bottom temperature 63.6° in Pujada Bay, eastern Mindanao. 

 It measures: Altitude, 1.3mm.; length, 1.3 mm.; diameter, 1.3 mm. 

 The pallet measures: Length, 4.6 mm., of which 1.2 mm. go to the 

 stalk; diameter, 0.7 mm. 



Another specimen of this species, Cat. No. 310971, U.S.N.M., was 

 collected by the same expedition at station 5252 in 28 fathoms from a 

 piece of wood taken on coral bottom, off Linao Point, Gulf of Davao. 



Subgenus Neobankia Bartsch 



1921. Neobankia Bartsch, Proc. Biol. Soc, Washington, vol. 34, p. 2(>. 



1922. Neobankia Bartsch, Bull. 122, U.S. Nat, Mus., p. 9. 



In Neobankia the pallets consist of cone-in-conc elements, covered 

 by a thin membrane, which is denticulate at the free margin. 

 Type. — Bankia (Neobankia) zeteki Bartsch. 



