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 maculz, 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 
Naturalisti 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 
