540 lU'LLKTIN 100, UNITED STATES NATIONAL MUSEUM 



cone; that is, the external portion is curved while the inner portion 

 is almost flat. The cavity of the cone extends to the insertion of the 

 stalk. The stalk is short and hears an expanded knob at its free 

 end. 



The type (Cat. No. 310975, U.S.N.M.) was collected in a piece of 

 wood dredged during; the United States Bureau of Fisheries Steamer 

 Albatross Philippine Expedition, at station 5252, in 28 fathoms on coral 

 bottom off Linao Point, Gulf of Davao, Mindanao. It measures: 

 Altitude, 2.2 mm.; length, 2.2 mm.; diameter, 2.2. The pallets meas- 

 ure: Length, 2.6 mm.; diameter, 1.3 mm., of which 1.2 mm. go to the 

 stalk. 



A lot of specimens from the same piece of wood are entered as Cat. 

 No. 246127, U.S.N.M. 



Subgenus Teredothyra Bartsch 



1921. Teredothyra Baktscu, Proc. Biol. Soc. Washington, vol. 34, p. 2fi. 



1922. Teredothyra Bartsch, Bull. 122, U. S. Nat. Mus., p. 22. 



In this subgenus the pallets "are doubly cupped at the terminal 

 portion. 



Type. — Teredo [Teredothyra) dominicensis Bartsch. 



TEREDO (TEREDOTHYRA) SMH HI, new species 



smith's teredo 

 Plate 53, figs. 6, 7; plate 56, fig. 4; plate 59, figs. 10, 11, 12 



Shell small, subglobular, milk-white, the extreme anterior margin 

 of the anterior part somewhat excavated and covered by a rather 

 thick callus which is partly reflected over the outside. Posterior to 

 this callus the anterior part is marked by ridges which radiate fan- 

 shaped from the callus posteriorly. They are closely approximated 

 anteriorly, the space between them widening posteriorly. Those on 

 the first half of the shell are much more distantly spaced than the 

 later ones, being about three times as far apart as the ridges them- 

 selves, while the later ones are about equal to the spaces that separate 

 them at their posterior margin. The free borders of these ridges are 

 finely denticulated. The spaces between the ridges are finely granu- 

 lose. The anterior portion of the median part is crossed by 28 

 strong, denticulated ridges which are separated by mere impressed 

 lines. Of these ridges, 21 are present in a straight line projected from 

 the ventral border of the anterior part across the anterior portion of 

 the median part. The individual denticles are doubly cusped at their 

 free margin. The middle portion of the median part is concave 

 and crossed by the attenuated continuations of the dental ridges 



