34 LAKE SUPERIOR. 



of other fishes, but unite by a ball-and-socket joint, as in reptiles. The 

 scales also resemble in some particulars those of the Crocodilean reptiles, 

 which immediately succeeded the fossil Ganoids, during whose epoch no 

 reptiles existed. The embryology of the gar-pike, of which nothing as yet 

 is known, would be an exceedingly interesting subject of investigation, since 

 it is a general law that the embryo of the animals now living resembles the 

 most ancient representatives of the same family. As probably connected 

 with the preservation of this ancient family of fishes in this country, may 

 be mentioned the fact that there was an extensive continent formed in North 

 America at a time when all the rest of the earth was under water. Thus 

 physical conditions have been more unaltered here than elsewhere. 



" The white-fish, ( Coregonus albus,) has all the characters of the salmons, 

 but no teeth. Among those I obtained to-day, is a new species, cha- 

 racterized by a smaller mouth and more rounded jaw. To the same family 

 belongs the lake " herring," which is no herring at all. This species has 

 a projecting lower jaw and is undescribed. Here is a little fish which on 

 hasty examination would seem to belong to the salmons, but has a project- 

 ing upper jaw, and teeth on the intermaxillary, the upper maxillary 

 forming another arch behind, without teeth. It has pectinated scales, like 

 the perch. It is a new genus, allied to the family of Characini of 

 Miiller. Fossil fishes of this family occur in great numbers in the creta- 

 ceous period ; they are the first of the osseous fishes. This again is an in- 

 stance similar to that of the Lepidosteus. The fish before us presents a 

 curious combination of the characters of the Cycloids and Ctenoids. Here 

 is a fish belonging to the CyprinidcB, but characterized by thick lips and a 

 projecting upper jaw, whence I propose to call it Rhinichthys marmoratus. 



" This fish, one familiar with the fishes of Massachusetts would suppose to 

 be a yellow perch, but it differs in wanting the tubercles on the head and oper- 

 culum. It is Perca acuta Cuv. In the tertiary beds are found Percoids, 

 with thirteen rays in the anterior dorsal ; this is also the case in the North 

 American species. Again the variety of minnows found in this country 

 has a parallel in the tertiary epoch." 



June 28th. To-day we made our first acquaintance with the 

 genuine black fly, a little insect resembling the common house-fly, 

 but darker on the back, with white spots on the legs, and two-thirds 

 as large, being about two lines in length. They are much quicker in 

 their motions, and much more persevering in their attacks, than the 

 musquito, forcing their way into any crevice, for instance between 



