548 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



The type (Cat. No. 246131, 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 5243 in Pujada Bay, eastern 

 Mindanao in 218 fathoms on gray mud, bottom temperature 63.6°. 

 It measures: Height, 1.4 mm.; length, 1.6 mm.; diameter, 1.4 mm. 

 The pallet measures: Length, 3 mm., of which 1.9 mm. go to the 

 stalk; diameter, 1.6 mm. 



Subgenus Lyrodus Gould 



1870. Lyrodus Gould, Invert. Mass., p. 34. 



1922. Lyrodus Bartsch, Bull. 122, U. S. Nat. Mus., p. 24. 



In this subgenus the terminal portion is not cupped, but ends in 

 two lateral forks, covered with a periostracum. 

 Type. — Teredo (Lyrodus) chlorotica Gould. 



TEREDO LYRODUS LINAOANA, new species 

 LINAO SHIPWORM 



Plate 55, figs. 1, 4; plate 57, fig. 6; plate 59, figs. 4, 5, 6 



Shell small, subglobular, white. The extreme anterior portion of 

 the anterior part forms a shallow sinus and is covered by a rather 

 thick callus which is reflected partly over the outer part of the ante- 

 rior area. Posterior to this callus the anterior part is crossed by 

 slender ridges which radiate fan shaped from the callus posteriorly, be- 

 ing closely approximated; in fact, fused at the callus and separated by 

 spaces a little wider than the ridges at their posterior margin. Of these 

 ridges there are 51 in the type and many have been lost by the ero- 

 sion at the umbone. These ridges are very finely denticulated at their 

 free margin. The anterior portion of the median area is narrow and 

 marked by slender denticulated ridges which are much narrower than 

 those on the anterior portion and are separated by mere incised lines 

 only. Of these ridges, 26 occur in a straight line across the anterior 

 portion of the median area parallel to the ventral margin of the an- 

 terior part. The individual denticles on these ridges are exceedingly 

 fine and closely spaced. The junction of the anterior portion and 

 the anterior portion of the median part forms a somewhat sinuous 

 line. The middle portion of the median part is almost as wide as 

 the anterior portion and is crossed by the continuation of the decid- 

 edly flexed dental ridges which here are without denticles. These 

 appear as a series of distantly spaced raised threads. The posterior 

 portion of the median part is considerably wider than the anterior 

 and middle portion of the median part combined, and is crossed by 

 the continuation of the strong lines that cross the middle median 

 portion, but here these threads become decidedly upturned. There 



