412 • BORER. 



leiifjjtli; the opening longitudinal, large, its length being the 

 half of the height of the body. Rays of the fin very numerous, 

 slender; those along the ventral line directed backward, on the 

 back curved, and at their points turned almost forward. There 

 is another fin, which may be termed preanal, between the vent 

 and the gill openings, formed of a fold of the skin, which 

 at its base contains a large number of very short rays, but 

 stout and blunt. While the fish is alive this fold of the skin 

 is moderately high, but when the body is distended with roe, 

 or when preserved in spirit, it becomes contracted and low. 

 The lateral line is at the sides of the belly, and contains large 

 glands, one hundred and eight in number, just below the skin, 

 but lifting it up and forming a beaded row, with an open pore 

 on the upper side, from which the slime is poured out. There 

 are no distinct teeth in the jaw, but some are deeply concealed 

 within the mouth. At its upper part is a single slender, 

 strong, and curved tooth, which is broad at the root and 

 covered Avith a fold of skin. The lower teeth are in regular 

 longitudinal rows, bent on each side, and two rows answering 

 to each other. In the outer row are eight, with sometimes 

 another of small size; in the inner row from eight to ten, the 

 two foremost stouter than the others. 



The nasal openings are among the barbs on the snout, and 

 are covered with a lobe above ; passing into a nasal cavity that 

 is marked with longitudinal folds through a cartilaginous tube 

 marked with a ring; (^Ir. Owen says with rings like the wind- 

 pipe;) and from thence to the entrance of the gullet, where is 

 a valve, and through which the water for breathing passes into 

 what we may term the gills; so that, as this author supposes, 

 there exists in this fish a sort of structvire through the nostrils 

 to what is equivalent to the gills, which is not found in any other. 

 But it appears to me that the difference in this respect between 

 the Borer and the Lamprey is rather in the circumstances than 

 the essentials of this organization; since the opening on the 

 head in the one performs the same function as what are termed 

 the nasal openings in the other, and both of them afford the 

 means by which water is conveyed to the gills; but in the 

 case of the Borer, as perhaps in the Lampreys, there are some 

 organic formations, as a veil to the palate, and some smaller 

 veils of a similar kind, which must greatly assist in rendering 



