66 VERMES. 



The length of the specimen was fifteen or sixteen inches, breadth 

 an inch, and thickness about a quarter of an inch ; the whole of a flat- 

 tened form, nearly linear, diminishing slightly both in breadth and 

 thickness towards the posterior extremity, which, like the anterior, is 

 obtuse. A thin border environs the body, which, sundered transversely, 

 is elliptical. 



The anterior margin of the animal is cleft horizontally in front by 

 a shallow groove, deepening as it descends some way down each side of 

 the head ; and there is a dilateable slit, a quarter of an inch long in the 

 under surface, near the extremity of the head, denoting the mouth. 

 Colour universally grey, darker on the upper surface ; the thin border 

 and under surface lighter. 



No specks or eyes were perceptible. 



This animal swims very actively in long, smooth undulations, the 

 edge or margin of the body being uppermost during its course around 

 the interior of its vessel, which will sometimes continue for hours. But 

 I cannot speak of its precise position, either in a vessel of large capacity, 

 or in the sea, not having witnessed it in either. Plate VI. fig. 1. Gordim 

 in motion ; fig. 2. transverse section, shewing the figure of the body. 

 Plate VII. fig. 1. under surface of anterior portion, shewing the form 

 and position of the mouth, and the marginal groove. 



After its lively exercise on the second evening, I found the animal 

 contracted, motionless, and apparently dead next morning, which was 

 the subject of no little regret, from not having had an opportunity of 

 obtaining a correct delineation, always so important in illustrating natu- 

 ral history. It allowed itself to be lifted by the hand without the least 

 resistance ; yet, when committed again to recent sea water in another 

 vessel, all its activity was resumed, which continued till a late hour of 

 the night, when both then, and from subsequent observation, I concluded 

 it to be of nocturnal habits. 



The alternate activity and quiescence of this creature are alike singu- 

 lar. Instead of the languid exertions and tardy motions common to the 

 vermicular genera, the gradual unwinding of the sluggish bodies of 

 some, and the extension of others from their secret retreats, the Gordiux 



