the Fishes of Massachusetts, 183 



Having carefully compared our common Shad with Yar- 

 rell's description of the Alosa communis, the points of resem- 

 blance were so numerous that I felt compelled to consider it 

 as identical with the foreign fish. Dr Dekay informs me that 

 it has been somewhere described as a new species, under the 

 name of sapidissima. 



I have but little doubt that a species of Sole a, Cuv., is 

 found in our waters, from the description given me, by Mr 

 Newcomb, of Gluincy Market, of a fish seen by him during 

 the last season. 



But a single specimen of the Achirus mollis had been 

 met with, when I concluded my Report, which was taken at 

 Holmes' Hole. In April, 1840, I received a beautiful speci- 

 men, six inches in length, with the transverse bands upon the 

 sides very distinct, which was caught at iXahant. 



A second specimen of the Echexeis, which I considered 

 the 7iauc?^ates I have seen within a few weeks. It was taken 

 at Hyannis, south side of Barnstable, Cape Cod. Dr Mitch- 

 ill's " Supplement*' has enabled me to identify this fish, as the 

 species described by him under the name of E. alha-cauda. 

 His description is rather a general one, but it is sufficient to 

 determine the species. 



Tetraodon mathematicus. Mitchill. Mathematical Tetra- 



odon. 



Mathematical Tetrodon. (Tetrodon mathematicus.) Mitcliill. Trans. Lit. 

 et Phil. Soc. N. Y. Vol. I. 474 et fig. 



A fine specimen of this beautiful species was taken at Nan- 

 tucket during the last summer, and now belongs to Mr Stack- 

 house of this city. Its entire length is twentythree inches : 

 its greatest depth is four and a half inches : its greatest width 

 across from the pectoral fin, is four inches. The head and 

 entire back, are of a deep olive-green color ; the sides are 

 silvery ; the inferior portion of the fish is of a pure white. 



The whole surface of the body is perfectly smooth, with 

 the exception of the space beneath, bounded anteriorly by the 

 throat, laterally by the pectoral fins, and posteriorly by the 



