- 75 - 



Dimensions .- Length, 3.5 mm.; alt., 2.5 mm,; semidiam., 

 1.2 mm. 



Remarks .- The single valve on which this species is based 

 is the first member of the genius to oe described from the Terti- 

 aries of the Antillean region. The ligament is assumed to be 

 opisthodetiG and therefore the umbo is described as prosogyrate, 

 T. call ip iota is smaller and less elongated t han ? . c;vtheree, Dall (1) 



(1). Bull. Mus. Oomot. Zool., Harvard, vol. 12,. pp. 254-255, vl. 

 8, figs. 1, la, 1886. 



and T^. amabilis Dall (2) of the recent Antillean fauna, and dif- 

 fers also in hinge characters. The Bovrden form, appears to resem.ble 



(2). idem, vol. 18, p. 438, pi. 40, fig. -\ 1889. 



more closely T. panamensis Dall (5) from the C-ulf of Panama, but 

 is less prorluced posteriori;; and is v.lthout the slight posterior 



(3). idem, vol. 43, no. 6, p. 388, pi. 17, fig. 10, 12. 



compression. 



Occurrence. - lor/cr Iv.iocene: Bowden beds, Bovrden, Jamaica. 



