628 SUPPLEMENT. 
22. Polygyra ponsonbyi. 
Polygyra ponsonbyi, Pilsbry, Proc. Acad. Phil. 1896, p. 17, t. 2. figg. 1-3 - 
Hab. Mexico, exact locality not known !. 
23. Polygyra euglypta. 
Polygyra euglypta, Pilsbry, Proc. Acad. Phil. 1896, p. 18, t. 2. figg. 7-9". 
Hab. N.W. Mexico: Sinaloa, Mazatlan !. 
24. Polygyra albicostulata. 
Polygyra albicostulata, Pilsbry, Proc. Acad. Phil. 1896, p. 18, t. 2. figg. 4-6°. 
Hab. Merxtco, exact locality not known!?. 
STROBILA (p. 172). 
Pilsbry has renamed this genus Strobilops, on account of Strodila being preoccupied 
by Sars for a stage of evolution of Medusa aurita; I do not think that this was needed, 
as Strobila, Sars, cannot stand as a distinct genus in the zoological system. 
LABYRINTHUS (p. 175). 
Pilsbry, in Tryon’s ‘ Manual of Conchology,’ (2) ix. pp. xxxv & 94, treats Labyrinthus 
as a section of Pleurodonte, Fisch. Waldh., of the tribe ‘‘ Epiphallophora.” ‘Teeth 
of the radula all unicuspid, as in Caracolus, according to Semper. 
Labyrinthus triplicatus (p. 176). 
Labyrinthus triplicatus, Biolley, Mol. terr. y fluv. de Costa Rica, p. 11°. 
To the localities given, add :— 
Hab. N.E. Costa Rica: San Miguel, on the road to the Rio Sarapiqui, about 500 metres 
(Biolley °). 
Pittier has sent me a specimen of it, measuring 27 millim. in diameter and 14 in 
height. 
Labyrinthus quadridentatus (p. 176). 
Labyrinthus quadridentatus, Biolley, Mol. terr. y fluv. de Costa Rica, p. 11°. 
To the localities given, add :— 
Hab. [S.W. Costa Rica:] Guaitil de Pirris, about 800 metres (Biolley >); Alto de Mano 
Tigre, near Terraba, 690-700 metres, in woods (Pittier); El Pozo, Rio Grande de 
Terraba, El Pital, Valley of the Rio Naranjo, 200 metres (Pittier). 
Var. minor. 
Diam. maj. 164, min. 14, alt. 10 millim. 
