504 PROCEEDINGS OF THE ACADEMY OF lAug., 



Notes on New or Imperfectly Known Species. 



Pleurodonte (Labyrinthus) otis (Sol.). PL XXXVII, figs. 5, 6, 7. 



Helix otis [Solander] in Skinner & Co.'s Catalogue of the Portland Museum, 

 1786, p. 38, lot No. 925, based solely on Favanne, La Conchvliologie, 

 pi. 63, fig. 11. 



Helix labyrinthus Chemnitz, Conchylien Cabinet, XI (1795), p. 271, pi. 208, 

 fig. 2048 (copied from Favanne). 



The typical form of this remarkable snail is figured. It is dis- 

 tinguished by the strongly recurved peripheral and axial ends of the 

 peristome and the spatulate shape of the aperture. Alt. 21, diam. 

 51 mm. 



Isthmus of Panama. No more exact locality is known, but the 

 form will probably be found in or near the Canal Zone. Several 

 more or less divergent races have been described from Panama and 

 Colombia, the status of which remains to be determined. A synopsis 

 of these forms follows. 



P. o. subplanata (Petit). 



Caracolla subplannta Petit de la Saussaie, Revue Zoologique, Aout, 1843, 

 p. 238 (Nouvelle Grenade) ; Magazin do Zoologie, 1843, Mollusques, pi. 68. 



Smaller than P. otis, alt. 14, diam. 40 mm., reddish brown. Aper- 

 ture as in otis, the peristome retracted at both ends. 



This Colombian form differs from typical P. otis by its diminished 

 size, but is probably not separable from the small Panamic form called 

 si pun cu lata. 



P. o. sipunculata ( Forbes). 



Helix labyrinthus variety sipunculata Forbes, P. Z. S., 1850 (March 26), p. 

 53, pi. ix, figs. 4a, 4b (Panama). 



Shell purple-brown, 35 mm. in diameter, decidedly smaller than 

 V. otis; aperture as in typical otis, the columellar and peripheral angles 

 of the peristome strongly recurved. 



This shell does not seem to differ very materially from the earlier 

 subplanata Petit. It is only provisionally admitted as a race. The 

 figure shows the umbilicus somewhat smaller, and the aperture not 

 exactly similar. It may, as Dr. Brown suggests to me, be a dwarfed 

 form of otis owing to unfavorable station. 



P. o. annulifera ('Pfr.' Reeve). 



Helix annulifera Pfeiffer, P. Z. S., 1851 (December 7, 1853), p. 260 (Panama) 

 Reeve, Conchologia Ieonica, Helix, pi. 100, fig. 555 (May, 1852). 



The shell is much smaller than P. otis, alt. 13, diam. 34 mm.; deep 

 chestnut colored with a broad white band at the acute keel. The 

 aperture is shaped as in P. otis; the peristome is retracted at both 



ends. 



