^OLis. 239 



dots of opaque white, olive, dark brown, purplish or yellowish (as if 

 sprinkled with Indian meal). Dorsal tentacles dark, of the same 

 length as the brancliia3, smooth, rapidly tapering, slightly retractile, 

 truncated at tip, which is yellowish or whitish and appears to be 

 hollow ; oral tentacles longer and more slender, brownish cream- 

 color, dotted near tip. Brancliia3 lanceolate, compressed, with 

 slight pedicle at insertion, arranged in numerous (twelve to twenty) 

 crowded, imbricated oblique series on each side, about ten to twelve 

 in each series, becoming shorter and paler downwards, somewhat 

 shorter and more crowded near the head, and reaching to the oral 

 tentacles, the exposed surface and edge mottled as before described, 

 the unexposed surface and edge pale flesh-color, tips pale ; central 

 portion of the back nearly naked, variously mottled and exhibiting 

 the large sac containing the heart, the pulsations of which (about 

 seventy-four per minute) are distinctly seen. Foot as broad as the 

 body, broad and gently curved in front, with the angles very slightly 

 prolonged, tapering gradually backwards to a very 

 fine point, extending a little beyond the branchiae ; '"' 



color pale pinkish, transparent. Head large, sub- 

 circular, pale yellowish ; mouth pursed ; tongue 

 short, broad at base, tapering obtusely to a point. Lingual dentition of s 

 composed of entire, arched plates having their 

 edge simply pectinated with simple denticles.* (Plate XYIII. 

 Fig. 260.) Length, ordinarily, two to three inches (sometimes 

 four) ; breadth, one third the length. 



Found among Actinia; and TubularicB in the Bath-house, Craigie's 

 Bridge, Boston, in April and May ; in the river between East Boston 

 and Charlestown, October to December (^Stimpson). It is doubtless 

 abundant elsewhere, as it is one of the most common species in 

 northern seas, certainly on the European side, where it is usually 

 found under stones between tide-marks. 



Its very great variation in size and color, from dark olive or 

 brown to flesh-color, with every variety of mottling, has given rise 

 to many names for it. I had designated it under the name of EoHs 

 fariiiacea (Plate XYIII. Figs. 257, 259, 263), on account of the 

 mottling, as if with Indian meal, of the first specimens I examined. 

 But the general and particular characters of form and habits, and 

 the unique denticulation of the tongue, lead me to believe it identi- 



* The figures pi-eparecl by Dr. Gould arc not satisfactory. Through the kindness of 

 Mr. Samuel Powel, of Newport, R. I., I am able to add Fig. 518, which correctly illus- 

 trates the denticles. — W. G. B. 



