FISHES OF LAKE SUPERIOR. 315 



hidden under the skin ; the whole dotted with black. The space 

 between the pectoral fins and the branchial opening is sensibly 

 reduced, and covered by the skin, the aspect of which is the same 

 as on the rest of the body. The thoracic arch is not visible ; we 

 have also scarcely found traces of the cuirass formed by the ascend- 

 ing branch of the innominated bones, and about the basis of the 

 ventral spines, which are perceived only with the magnifying glass, 

 under the form of very small hooks. 



It was difficult to count the exact number of the rays of the fins, 

 as they are very thin and slender. We have, however, recognized the 

 existence of at least six dorsal spines ; the last of which is well devel- 

 oped, and has a small membrane at its posterior margin, arising 

 from the summit of the spine to unite the basis of the soft dorsal. 

 This latter seems to have seven rays, composing a triangular fin, whose 

 posterior angle rests on the tail. The anal has the same form, 

 but is somewhat smaller, opposite to the dorsal, and provided with 

 six rays. The caudal is short, rounded, and has twelve rays, perhaps 

 even fourteen, for the two exterior ones appeared to us almost twice 

 as thick as the others. The pectorals are pointed, and have eight 

 rays of an extreme thinness. As for the ventrals, as we have seen 

 above, they are only visible with the magnifying glass, and all we 

 have been enabled to do was to satisfy ourselves of the presence of 

 the spinous ray common to all species. 



Three individuals of this species were found at Michipicotin. Two 

 from among them are only one-quarter of an inch long. 



ESOCID,E, (The Pickerels.'} 



The family of pickerels is perhaps the least understood of any in 

 the whole class. From the characters assigned to it bv Cuvier. it 



C3 * 



contains a variety of fishes, which can scarcely belong to one and the 

 same natural group, and indeed more recent investigators, as, for 

 instance, Joh. Miiller, have divided the Esoces of Cuvier into two 

 families, on the ground of the pseudo-branchiae ; so that we have 

 now the families of Scomberesoces in addition to the true Esoces. 

 Several isolated genera formerly referred also to the family of the 

 Esoces, have either been removed to other natural groups, or become 



