234 BULLETIN OF THE 



Genus MODIOLA Lamarck. 

 Modiola polita Verrill and Smith. 



Plate VI. Fig. 3. 



Modiola polita V. & S., Am. Journ. Sci., XX. pp. 392, 400, Oct. 25, 1880. Verrill, 

 Proc. U. S. Nat. Mu8., IIL 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). 



Modiotaria polita Verrill, Trans. Conn. Acad., VI. p. 281, pi. xxx. f. 12, 1884. 



Modiella polita Monterosato, Nora. Conch. Medit., p. 12, 1884. 



Modiola {Ami/gdalum) lutea Fischer, Man. Conchyl., p. 968, 1885. 



Habitat. North Atlantic. I\Iediterranean (Monterosato) ; Gulf of Gascony, 

 and Marocco coast, Bay of Biscay (Fisclier) ; New En<,'land coast (Verrill) ; 

 Gulf of Mexico and Antilles (Blake Exp.), Station 4.3, 339 fins., 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, tliey 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 striae. 



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 

 papillae ; 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. 



