28 BULLETIN 122, UNITED STATES NATIONAL MUSEUM. 



TEREDO (TEREDOPS) FLORIDANA, new species. 

 FLORIDA SHIPWORM. 



Plate 22, fig. 1 ; plate 34, fig. 1. 



Shell small, subglobular, white. The extreme anterior area of the 

 anterior part with a shallow sinus, which is heavily calloused. 

 Callus reflected outward, but not forming a distinct ridge. The an- 

 terior part is marked by a series of slender dental ridges, which 

 have a strong downward trend, rather more distantly from the edge 

 than in any other American species, and then spread fanlike back- 

 ward. At the posterior border they are as wide as the spaces that 

 separate them.. Of these ridges there are 84 in the type. They 

 slope abruptly on the upper side, and a little less so on the ven- 

 tral, and are fringed at the free edge by exceedingly fine denticles. 

 The posterior median area is very broad, almost equaling the ante- 

 rior area in width, and crossed by dental ridges which are separated 

 by mere lines only, and provided with numerous rather fine denticles. 

 The middle median portion is marked by very rough wrinkles, while 

 the posterior portion is feebly wrinkled. The latter is about as wide 

 as the anterior median portion. The posterior part is joined to the 

 posterior median portion by a thickened tumid area and forms a 

 very small, inconspicuous auricle which is marked by lines of growth 

 only. Interior bluish white, the junction of the anterior and median 

 portion is marked by a tumid cord, while the slender auricle projects 

 slightly over the posterior median area as a thin shelf. The umbones 

 bear a thick knob, from the inside of which a very broad, short blade 

 extends obliquely downward. This blade has a constricted neck by 

 which it attaches to the umbone. The ventral margin of the median 

 portion bears the usual knob. The pallets are spatulate, with the 

 stalk cylindric, the outer portion rounded, while the inner surface 

 is flat. The distal portion consists of a strong cone-shaped mass of 

 periostracum, with a certain amount of calcium at its free termination. 



The type and a lot of additional specimens. Cat. No. 193031, 

 U.S.N.M., come from a palmetto pile, which was said to have been 

 driven 12 years, at Tampa, Florida. 



The type measures : Height, 4.5 mm. ; length, 4.7 mm. ; diameter, 

 5 mm. The pallet measures : Length, 4.3 nun., of which 2.3 mm. 

 belong to the stalk; diameter, 1.1 mm. 



Another specimen. Cat. No. 36047, U.S.N.M., was obtained by 

 Henry Hemphill at Cedar Ke^-s, Florida. 



This is the only Teredops so far reported from East American 

 waters. 



