and Shells of Massachusetts Bay. 67 
Eoris BOSTONIENSIS. 
Plate I. fig. 1. 
E. corpore oblongo, capite brevi, tentaculis quatuor, branchiis cirri- 
formibus, purpureis, apicibus albis, utrinque fasciculis quinis; pede 
amplo, ein peracuto; tentacularum caudeque extremitatibus 
cyaneo tinc } 
PRR thirty-one twentieths, expanded breadth of 
of foot seven twentieths of an inch. 
Hab. Tide water of Charles River, Mass. 
My own collection. 
Cabinet of Bost. Soc. of Nat. History. 
Description. Body oblong, posteriorly attenuated, 
rounded on the back, in about the centre of which is a 
slight protuberance, apparently covering the heart, and 
rising and falling with a regular pulsatory (qu. respiratory ?) 
movement; color a faint brownish white; head short, 
depressed, under side sub-orbicular, furnished with four 
tentaculæ, two of them lateral and frontal, smooth, of a 
lake. color and beautifully tinged in the middle with 
azure ; the other pair situate on the back of the head, 
of a dark flesh color, flattened and serrated at the sides 
and. possessed of considerable contractility ; the eyes, 
which are black and very minute, are placed laterally and 
posteriorly near. their base ; all the tentaculæ are quite 
long, and taper to a point ; the mouth is large and fleshy, 
placed perpendicularly ; lips thick, bright flesh colored, 
of an hemispherical form, with their convex portions 
contiguous ; beneath the mouth and between that and the 
foot, are placed two labial or oral appendages, about one 
fourth of an inch in length, which are entirely separate 
from the foot and extend across and beyond it; the bran- 
