88 TETHYS-WEST AMERICAN. 



mit, forming a strongly serrate tuft. The opercule or mantle is 

 ovoid, rather elongate, and presents a moderately-developed expan- 

 sion on the right. Anterior tentacles are quite broad, plate-like, 

 with sinuous, lobed margins, and are moderately separated. The 

 posterior tentacles are conic and closer together. Swimming lobes 

 strongly developed. 



Genital orifice under the opercle in front of the gill. Opaline 

 gland of the grape-bunch type, opening by one orifice. 



Color: the body is bestrewn with numerous rather large oval 

 dark maculae, and spotted with smaller white spots. 



Shell concave, elongate, rounded at the anterior extremity, the 

 beak projecting and ronnded ; sinus notably arcuate. 



Island of San Lorenzo, near Callao, Peru. 



Aplysia chierchiana MAZ. & Zuc., Bollettino della Societa di 

 Naturalist! in Napoli, ser. 1, vol. iii, p. 52 (1889). 



T. PANAMENSIS Pilsbry, n. sp. PL 60, figs. 45, 46, 47, 48. 



Length (of alcoholic specimens) 4 to 6 cm. Body soft, of usual 

 proportions. Buccal lobes large, triangular-ear-shaped, with the 

 usual fold above. Tentacles lance-shaped and slit. Swimming 

 lobes thin, rather small, arising at the anterior third or two-fifths 

 the total length, uniting behind only at their junction with the foot. 

 Mantle transparent, with a very minute, scarcely visible pore; its 

 posterior right margin bilobed and sinused to form an excurrent 

 siphon. Genital pore and groove as usual. Opaline gland opening 

 by a single conspicuous orifice. 



Color grayish, with some ill-defined spots or rings, and marks of 

 black posteriorly on the lobes. Mantle immaculate, but there are 

 some faint, dark markings on inside of swimming lobes. 



Shell moderately convex, buff outside, having a moderately solid 

 calcareous layer within, the cuticle projecting but little beyond it. 

 Apex acute, projecting, bearing a callous reflexed crest which forms 

 a triangular cavity on the back. Sinus short and deeply arcuate. 

 Surface with slight growth-wrinkles and impressed unequal, irregu- 

 lar, radial grooves, several on the left slope deeper. Length 16, 

 breadth 13 mill. 



Panama (J. A. McNeill). 



The tentacles are comparatively slender and long ; the swimming 

 lobes weak, and the shell, with its hood at the summit, is about as 

 solid as in T. punctata Cuv. No other West Coast or Antillean 



