114 



but when contracted the body is covered with transverse wrinkles, 

 composed of minute rugosities, which are much the largest toward 

 the posterior extremity. On the ventral surface there is a longi- 

 tudinal, depressed line along the middle. A pair of small, slen- 

 der hooks, usually retracted within their sheaths, are found close 

 together, below, anteriorly, one on each side of the median line. 

 The produced labium, or spoon-shaped oral process, which makes 

 this genus so remarkable, is largely developed, and half as long 

 as the body, even when contracted ; but it can be extended to two 

 or three times this length, and proportionally increased in breadth. 

 It then resembles a broad curving membrane, of a transparent 

 whitish color, with undulating margins and a somewhat pointed 

 extremity. Its edge is distinct and transparent, giving it the 

 appearance of being surrounded by a marginal vessel. Its cur- 

 vature, and undulating sides, are caused by the central portions 

 being less extensible than the other parts. This organ is kept in 

 constant motion, and its concave or lower surface is often applied 

 to the surface of other bodies, like the foot of a gasteropod. It 

 is easily detached from the body, and in that condition retains its 

 vitality for some time. When found separate it might easily be 

 mistaken for some strange Planaria. 



The length of this singular animal was two inches, including 

 the labium; the greatest breadth of the body, half an inch. It 

 forms its holes in indurated ferruginous sand, about six inches 

 below the surface, in the third subregion of the littoral zone. 

 Specimens occurred at Fort Johnson, in Charleston Harbor, in 

 March, 1852. 



Arenicola cristata, Stimpson. 



The species here described was found by Lieut. Kurtz and 

 myself on the shore of Maurice's Island, inside of Pelican Point, 

 at the entrance of Charleston Harbor. It is a large and fine 

 worm, probably the largest of its genus, as it grows to a length 

 of sixteen inches, with a thickness of one inch. It is rather 

 surprising that so large an animal should have been overlooked, 

 especially as it is not uncommon in the localities where it occurs. 

 It is the second species of the genus occurring on our coast, for 

 A. piscatorum is now known to be an inhabitant of Massachusetts 

 Bay. 



