Dentition. 



The dentition of the Ophisurus differs so entirely from that of the eel, as to 

 remove it from the same class or order of fishes, but it would be a great stretch 

 of classification to place him With the serpent, on account of his peculiar 

 dentition. The teeth are all conical, but vary in size, evidently suited for 

 seizing, killing, and retaining the prey. I conclude that the food will consist 

 of crustaceous insects of considerable size, which will be swallowed entire, to 

 be acted npon by the juices from the inner surface of the capacious stomach. 

 On the alveolar (dentary) margin of the npper jaw, and on the expanded 

 extremity (Fig. 6) there are seven teeth, an azygos tooth, and three on each 

 side, which gradually increase in size as they leave the mesial line ; a 

 vacant space corresponding to the contraction of the jaw, above alluded to, is 

 followed by a series of minute teeth. On the mesial line of the jaw, a 

 peculiar arrangement occurs, in a line with the azygos tooth, one a little larger 

 follows, then two minute teeth, then a tooth still larger than the first, followed 

 by an empty space, then a tooth still larger than its predecessors, and then an 

 empty space, then a tooth less than its predecessor, which is followed at a little 

 distance by a smaller one, and a series of minute teeth follow, becoming 

 gradually microscopic. The entire mesial series, above described, are embedded 

 in a groove, occupying the entire length of the base of the skull, and approaching 

 closely to the first vertebra of the spine. The transcendental anatomist would 

 call these teeth vomerine, but I shall continue to look for the vomer, in 

 connection with, and performing its usual function, as dividing the nostrils. 



The lower jaw (Fig. 7) supports three teeth on each side, corresponding to 

 those on the upper jaw, and leaving a space at the symphysis for the azygos 

 tooth. 



The alveolar (dentary) edge then supports a series of minute teeth of 

 beautiful regularity, resembling a fine saw, or comb. 



The tongue is edentulous, but the pharyngeal bones are covered with minute 

 teeth ; a series of a slightly increased size, bordering the external margins of 

 these bones. The arrangement, no doubt, when brought together by the 

 action of the pharyngeal muscles, in performing the act of swallowing, 

 subjecting the shrimp to a severe scrutiny, not only touching its quality, but 

 its vitality. 



THE VERTEBRAL COLUMN. 



In order to facilitate description, and avoid repetition of terms, I 

 propose to describe the Ophisurus as presenting a dorsal and abdomi- 

 nal margin, and right and left lateral surface, as being equally applic- 

 able to the skeleton, as to the external surface of the body. The 

 osseous tissue approaches that familiar to the anatomist as the semi- 

 cartilaginous, although each individual vertebra is well defined by a perfectly 

 formed articulation ; and the canal for the spinal marrow is composed of a 

 texture more resembling the shell, in hardness, than bone. In viewing a 

 separate vertebra (Fig. 3a), the spinal canal will be observed nearly as large 

 as the articular surface of the body of the vertebra, and the proportions 

 still continued throughout the entire spine. A mere rudiment of the spinous 

 process exists, and a fibrous membrane of considerable extent separates the 

 interspinous processes and fins, from the vertebrae. On the abdominal line 

 (Fig. 36) on each side, a plate, or process, extends, and presenting a convex 

 free margin to which is articulated an exceedingly delicate rib, the ribs, 

 indeed, more resemble a fine hair than a bone, and do not admit of drying so 

 as to be seen in the skeleton. 



Fig. 3 c is a lateral view of three of the vertebrae, and exhibits the 

 rudimentary state of the spinous processes, and the fibrous membrane separating 



