FISH-FORMED SIREJiT. 6l3 



perhaps no other than the Larva or Tadpole of 

 some large American Lizard, seems a scarce less 

 singular and curious animal than the Siren, so 

 much and so long the subject of dubious specu- 

 lation to Linna3us, and for which he at length 

 instituted his additional order termed Mcantes. 

 In its general appearance it bears some resemblance 

 to the larva of the Rana paradoxa, but is fur- 

 nished with gills, opening externally in the man- 

 ner of a fish : the openings are very large, and 

 the operculum or external flap is continued from 

 the sides of the head across the throat beneath, 

 so as completely to insulate the head from the 

 breast : the gills themselves consist of four semi- 

 circular bony or cartilaginous arches, Av^hicli are 

 denticulated or serrated on their internal or con- 

 cave part, like those of fishes : on the opercula 

 or external flaps are situated three very large 

 and elegant branchial fins or ramified parts, di- 

 vided and subdivided into a vast number of slen- 

 der or capillary processes. In these particulars 

 it resembles the Siren lacertina, except that in 

 that animal the external opening to the gills is 

 very small : the mouth is furnished in front with 

 a row of extremely minute teeth : the tongue 

 is large, smooth, and rounded at the tip : the 

 rictus or gape, when the mouth is closed ap- 

 pears considerably wider than it really is ; owing 

 to a lateral sulcus proceeding from each corner 

 to some distance : the feet are entirely destitute 

 9f webS; and the toes are furnished with weak- 



