188 Couthouy’s new Species of Eolis. 
near its junction, and two short, rounded, smooth ones, 
situated on the back of the head, a short space in the 
rear of the first pair; between them, just behind this 
shorter pair, are the eyes, black and so minute as to be 
nearly imperceptible without a lens ; the mouth is ver- 
tical, formed by two fleshy, contractile lips, covering a 
thin, corneous jaw adapted for cutting ; between these 
lips, a narrow, black, lingual ribbon is coin in mo- 
tion. The foot is but little wider than the body, and 
extends its whole length, being divided on each side at 
its commencement, so as to form two dilatable, tentacu- 
liform processes. The branchial cirri, slender, exter- 
nally transparent, internally of a beautiful orange, 
slightly retractile and tubular at their extremities, are 
disposed in double ranges along the sides of the back to 
the number of about ninety, those placed externally 
being considerably shorter than the inner ones ; between 
these are irregularly scattered numbers of yery short 
ones. The genital orifice is large, placed just behind 
the neck on the right side; the excretory duct opens a 
short distance behind and below it. 
Length one and four sae breadth seven twen- 
tieths of an inch. : 
Inhabits Massachusetts Bay; Chelsea Beach. 
OBSERVATIONS: "This species, hióh was found last 
spring among the roots of Laminaria saccharina, owing 
to the similar coloration of the branchial cirri, has much 
resemblance in its general aspect to E. salmondcea, 
Mihi, described at p. 68, tab. 1, f. 3,4. It will be 
found, however, on closer examination, to differ very 
materially in the form and position of the tentacula. 
