86 TETHYS—-WEST AMERICAN. 
Guppy (in Proc. Sci. Asso. Trinidad, ii, p. 1387, and Proc. Vic- 
toria Institute of Trinidad, pt. 2, March, 1895, p. 123) reports this 
species from Trinidad, but there cannot be much doubt that the 
identification was erroneous. 
T. RANGIANA d’Orbigny. PI. 19, figs. 34, 35, 36. 
Length of the larger individuals 3 to 4 cm. Body very short 
and elevated, oblong, quite leathery, much swollen; head wide ; 
buceal tentacles broad and short, obtuse; foot oblong, wrinkled, 
truncate in front, very broad and rounded behind. Swimming 
lobes short, united behind for the greater part of their length, form- 
ing a deep sack. Mantle large, oval, without tongue-like process, 
the posterior margin with a fleshy circle elevated in perpendicular 
crests. A very large oval aperture in the mantle shows the shell. 
Gill partly covered. : 
Color in alcohol blackish. 
Shell ovate, swollen, cretaceous, nearly smooth, the apex arcuate ; 
yellowish. 
Payta, Peru, in 6-7 fms., sand bottom (Dupetit-Thouars). 
A. rangiana ORB., Voy. dans l’Amér. Mérid., p. 210, pl. 17, f 11- 
18. 
This species, Orbigny writes, has great affinity with A. nigra, and 
may prove to be the young of that; but the foot is not produced 
behind, and the aperture of the mantle is six times as large, 
although the individuals are not more than one-eighth the size of 
A. nigra. It was described and figured from alcoholic specimens. 
T. ressontt Rang. PI. 56, figs. 15, 16, 17. 
Length 17 em. Body much elevated, fleshy ; not as much elon- 
gated in front as in most other species, short and acute behind. 
Smooth and grayish-rose colored, with fine reddish lineolation. 
Foot oblong. Swimming lobes very large. Anterior tentacles 
thick and not very susceptible of extension ; hinder tentacles lanceo- 
late, marked in the middle by a black line extending their entire 
length. Mantle with a small subcentral tube, and terminating be- 
hind in a small, open siphon. 
Shell oval, pointed behind, concave with little-developed apex ; 
sinus long and not much arched. Inside white and covered with a 
calcareous layer; outer surface amber colored. Length 34 mill. 
Payta, Peru (Lesson). 
