50 NATURAL HISTORY 



(Lampetra parva et fluviatilis B J, and the stickle-back 

 (Pisciculus aculeatus g ). 



To enable the reader to distinguish between them, their specific dif- 

 ferences may be thus noted. 



In the sharp-nosed eel, Anguilla acutirostris, YARR., the snout is acute, 

 and compressed at the sides ; the gape does not extend farther back 

 than the middle of the eye ; and about one-third of the entire length of 

 the fish is situated in front of the commencement of the dorsal fin, and 

 between one-eighth and one-ninth before the pectorals. This species is 

 common throughout the country, and attains a considerable size ; mea- 

 suring two, three, or four feet in length, and sometimes more. 



In the broad-nosed eel, Ang. latirostris, YARR., the snout is broad and 

 rounded ; the gape extends as far backwards as the hinder edge of the 

 orbit; and more than one-third of the entire length of the fish is in front 

 of the dorsal, and one-seventh in front of the pectoral fins. It rarely 

 exceeds two feet in length ; and appears to be almost equally common 

 with the preceding. 



In the snigeel, Ang. mediorostris, YARR., the snout is rather long and 

 moderately broad ; the gape does not extend quite so far back as the 

 posterior edge of the orbit; there is rather less than one-third of the 

 entire length of the fish before the dorsal, and between one-seventh and 

 one-eighth before the pectoral fins. 



Mr. Yarrell's specimens of the last were obtained from the river Avon. 

 It appears not to acquire so large a size as either of the others ; seldom 

 exceeding half a pound in weight: while the broad-nosed eel has been 

 known to weigh five pounds, and the sharp-nosed has even acquired the 

 enormous weight of twenty-eight pounds. 



The more extensively these characters are tested in different localities, 

 the more assured will be our knowledge of the species of eels, of their 

 distribution, and of their habits : all subjects of considerable interest. 

 E. T. B. 



8 [Ammoccetes branchialis, DUM.] 



8 On the stickle-back of the text a remark must be made, similar to 

 that which was elicited by the eel. Where, in the days of Gilbert White, 

 only one species was believed to exist, it is now known that there are 

 several. Cuvier clearly distinguished three, and indicated others, that 

 had previously been confounded under the common name of Gasterosteus 

 aculeatus ; and Mr. Yarrell subsequently made known the fact that these 

 several kinds were found in England also. In his History of British 

 Fishes he has given figures and descriptions of four different kinds of 

 three-spined stickle-back s, as well as of a four-spined species. The 

 latter was obtained from the neighbourhood of Edinburgh, and is 

 regarded as altogether new; it is the Gast. spinulosus of Messrs. Yarrell 

 and Jenyns. 



It is easy to distinguish between the several kinds of three-spined 

 stickle-backs, if attention be paid to the manner in which their sides are 

 covered. If the bony plates which spread away from the lateral line 



