240 PROCEEDINGS OF THE NATIONAL MUSEUM vol. S5 



shines through the integument of the aniinal as a rosy flush behind the 

 tentacles. Sole of foot smoke-gray, medially longitudinally cleft; 

 locomotion of the two sides alternate. 



The animal at rest usually suspends itself by a nuicous thread. 



TURRITHYRA, new genus 



Shell Large, elongate-turreted, unicolor, axially or spirally banded, 

 or both, with axial and spiral riblets and threads whose junction 

 may or may not form tubercles or short spines. Sutures minutely 

 tufted. Aperture large, broadly oval or subcircular; peristome 

 double, expanded to a varying degree in the different species. A 

 breathing pore may or may not be present. 



Type: Turrithyra {Tunnthyra) canaliculata (Gundlach) Pfeiffer. 



This genus is readily divisible into three subgenera, as indicated 

 by the following key : 



KEY TO THE SUBGENERA OF TURRITHYRA 



Breathing ])ore present. 



Inner lip cnt, posterior half reflected over umbilicus Turrithyretes 



Inner lip not cut, posterior half not reflected over umbilicus Turrithyra 



Breathing pore absent Turripoma 



Turrithyretes, new subgenus 

 Those Turrithyras that possess a breathing pore and have the 

 inner lip cut with the posterior half reflected over the umbilicus. 

 Type: Turrithyra {Turrithyretes) sinuosa (Wright) Pfeiffer. 



KEY TO THE SPECIES OF SUBGENUS TURRITHYRETES 



Shell Strongly echinulate echinulata 



Shell not strongly echinulate sinuosa 



TURRITHYRA (TURRITHYRETES) ECHINULATA (Wright) Pfeiffer 



Shell red or reddish, unicolor or spirally banded, with the peri- 

 stome white or pale yellow. Nuclear whorls decollated in all our 

 specimens. Postnuclear whorls inflated, well rounded, marked by 

 slender, retractively slanting axial and spiral threads, the junction 

 of which forms strong spines or cusps whose tips are retractively 

 curved. These cusps continue undiminished over the last whorl and 

 its base. Peristome double, the outer broadly expanded and re- 

 flected, radially fluted and marked with incremental lines. That of 

 the posterior half of the inner lip is reflected over and covers the 

 umbilicus. The inner peristome is less extensive, it is also reflected 

 and adnate to the outer. 



The exact type locality of the typical race is unknown. "Vig- 

 nales," the locality given, is a rather broad designation as we now 

 understand it. The lesser race comes from the Sierra del Abra. 



