534 Miscellanea Zoologica. 



to infer, from its analogy with the Planariae,* that it belongs to the 

 circulating, and not to a nervous system. I have never detected 

 the slightest appearance of a fluid in motion in any of the vessels ; 

 and were I to call the central vessel an aorta, and to decide that the 

 lateral vessels were for the purpose of returning the refluent fluid 

 to the heart, I might justly be censured for indulging in a fancy 

 which has no observation in its support. We are too liable to as- 

 sign to the organs of these lower creatures the names of what we 

 deem their analogues in higher classes, and with the name to as- 

 sociate an idea of sameness or identity in their functions, — a pro- 

 pensity which has not seldom led to error. 



The Nemertes live under stones and in mud between tide marks : 

 they avoid the light, and love obscurity. They are numerous in in- 

 dividuals, but how they are propagated is yet conjectural. At cer- 

 tain seasons I have seen within the body small roundish oviform 

 grains lying unconnected with any particular viscus, but of the real 

 nature of these, no observation has enabled me to form an opinion. 

 Specimens have also occurred in which there seemed to be a begin- 

 ning separation of the body into two or more parts, but these marks 

 of division might be the effect of injury. The species are very te- 

 nacious of life : if cut into several pieces, each lives and moves, and 

 perhaps in time each will grow up to a complete and perfect worm. 

 When placed in fresh water they shew, by instant contortions, how 

 painful and poisonous is this fluid to them. They soon break into 

 pieces, disgorge portions of the viscera, and speedily die and dissolve 

 into a soft jelly. 



* A gizzard near the centre of the alimentary canal, armed with 



spines. — Subgenus Nemertes. 



] . N. gracilis, of a uniform olive-colour, very long and filiform ; 

 eyes numerous. (Plate XVII. Fig. 1.) 



Hab. Under stones near low water-mark. Berwick Bay. 



This worm, when drawn out to its ordinary length, as in the act 

 of creeping, measures about 20 inches, while it is not more than a 

 line in breadth : body linear or somewhat attenuated at the posterior 

 extremity, compressed, smooth, soft and glutinous, very contractile, 

 of a uniform olive-green colour, lighter on the .ventral surface ; when 

 viewed through a common magnifier it is seen to be marked with 

 numerous pale cross lilies, and the sides appear lighter than the cen- 

 tre : head obtuse, rounded in front, tinted with yellow, and dotted 

 with numerous eyes along each side reaching to the two orange-co- 



* See figures illustrative of this in Rogefs Biidgew. Treat, ii. p. 250, fig. 

 ;}46 ; and in Cyclop, of Anat. and Physiology, i. p. 653, fig. 327. 



