86 TETHYS-WEST AMERICAN. 



Guppy (in Proc. Sci. Asso. Trinidad, ii, p. 137, 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. PL 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 ; 

 buccal 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 frns., sand bottom (Dupetit-Thouars). 



A. rangiana ORB., Voy. dans PAmer. Merid., p. 210, pi. 17, f. 11- 

 13. 



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. LESSONII Rang. PI. 56, figs. 15, 16, 17. 



Length 17 cm. 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). 



