234 BULLETIN OF THE 
Genus MODIOLA Lamarck. 
Modiola polita Verrixt and Smits. 
Plate VI. Fig. 3. 
Modiola polita V. & S., Am. Journ. Sci., XX. pp. 392, 400, Oct. 25, 1880. Verrill, 
Proc. U.S. Nat. Mus., III. p. 402, 1881; Dall, Bull. M. C. Z., IX. 
p. 116, 1881; Verrill, Trans. Conn. Acad. Sci., V. p. 578, July, 1882. 
Mytilus luteus Jeffreys, Rep. Brit. Assoc. Adv. Sci., 1880 (name only), Ann. Mag. 
Nat. Hist., Oct. 1880, p. 315 (name only). 
Modiola lutea Fischer, Journ. de Conchyl., Jan. 1882, p. 52 (described). 
Modiolaria polita Verrill, Trans. Conn. Acad., VI. p. 281, pl. xxx. f. 12, 1884. 
Modiella polita Monterosato, Nom. Conch. Medit., p. 12, 1884. 
Modiola (Amygdalum) lutea Fischer, Man. Conchyl., p. 968, 1885. 
Habitat. North Atlantic. Mediterranean (Monterosato); Gulf of Gascony, 
and Marocco coast, Bay of Biscay (Fischer); New England coast (Verrill) ; 
Gulf of Mexico and Antilles (Blake Exp.), Station 43, 339 fms., off Tortugas, 
bottom temperature, 45°.0 F.; Station 47, 321 fms., bottom temperature, 46°.5; 
on the European side to over 1000 fms. The young were obtained rather 
abundantly at Station 2644, near Cape Florida, in 193 fms., by the U. S. Fish 
Commission. 
This very elegant mollusk attains a length of 50.0 mm. (2 inches) without 
marked change of proportions from the very young to the adult stage. The 
smallest are waxen translucent; as they grow older, some of them may be 
prettily maculated with sagittate opaque white spots, radiating in a reticulate 
manner from the beak. As they attain maturity, they take on a magnificent 
golden brown color, especially deep toward the anterior end. The shell is 
pearly white, all these colors being situate in the epidermis, which, usually 
very polished and smooth, in rare cases may be somewhat irregularly radiately 
striate with the finest striz. 
The soft parts of this species are delicate, and contain but little solid matter 
compared with the capacity of the valves. The four labial palpi are moderate 
and lamellated ; the gills, two on each side, extend the whole length of the 
animal, the inner lamina on each side being somewhat shorter than the outer 
one; the mantle margin is thin, smooth, and simple; the single branchial 
opening has (in alcohol) one hardly perceptible row of inconspicuous rounded 
papille ; the mantle behind the commissure of the branchial orifice is com- 
pletely open; the muscles are slender, the posterior adductor the largest, then 
the pedal and the anterior adductors, in that order; the foot is nearly half as 
long as the shell, longitudinally wrinkled, digitiform, very slender ; the pointed 
tip is grooved, the byssal socket at the base is strongly marked. This long and 
slender foot is well adapted for nest-weaving, in which this species excels. 
