216 



OPHELIACE.E. 



of which the feet are arranged in a single series. Head none. An- 

 terior extremity pointed, with a small obtuse mucro. Mouth inferior. 



No. XXXIX. 



Ophelia acuminata. 

 2 



1. Worm natural size. 



2. Magnified. 



about a line behind the snout, without a proboscis or jaws. Anal 

 extremity curved, somewhat spoon-shaped, cartilaginous, and marked^ 

 with transverse lines, and fringed beneath, on the margin, with a series 

 of minute tentacular cirri. Feet about forty on each side, rather 

 distant, and equally distanced, laid obliquely backwards, and appearing 

 to be articulated to the body by a very slightly bulbous base. Each 

 foot (No. XL. fig. 4) consists of a small papilla, whence issue two bun- 

 dles of very unequal bristles, a greatly elongated superior cirrus, and a 

 very short inferior cirrus in the form of a lobule. The superior cirrus 



No. XL. — Ophelia acuminata. 



3. Side of body and feet magnified. 



4. Foot and bristle more magnified. 



is tentacular, gently curved and tapered *. The bristles are all simple, 

 very slender, slightly curved, very acute and smooth. The longest 

 are much shorter than the superior cirrus. They form the inferior 

 bundle ; and the bristles of the superior bundle are comparatively 

 short. There are no spines in either bundle. 



The simplicity of this worm is an obstacle in the way of its 



* What we have described as the superior cirrus, Oersted would consider to be 

 the branchia;. 



