430 PROCEEDINGS OF THE ACADEMY OF 



Localities. In the Marshall Sandstone, at Battle Creek, Liberty (Jackson 

 county), Moscow, near Napoleon and at the Gritstone Quarries, at Pt. aux 

 Barques, with Rhynchonella camerifera. 



Besides the species already enumerated from the Marshall group there yet 

 remain a few too imperfect for adequate description, or belonging to classes 

 not yet investigated. Among these are Lepidodendron and Neuropteris9 ; a 

 coralline structure, encrusting, foliaceous or branching, with minute, short, 

 crowded polygonal cells -0088 of an inch in diameter, without visible 

 lamellae, but with some indications of transverse floors ; some undetermined 

 Lamellibranchs ; two ' sorts of Chiton-like scales ; two or three Nautili, 

 of which one is nodulous ; and sundry remains of spines, teeth and bones of 

 fishes. 



University of Michigan, July 1, 1862. 



Synopsis of the CARANGOIDS of the Eastern Coast of North America. 



BY THEODORE GILL. 



In the preparation of the " Catalogue of the Fishes of the Eastern Coast of 

 North America, " I trusted almost wholly to previous naturalists for that portion 

 relating to the species of Scombroids and the allied groups. Drs. Dekay, Hol- 

 brook and Girard having each introduced supposed new forms, it was to be 

 presumed that they had studied the species in their various stages. My 

 attention having been since attracted especially to the Carangoids, it has 

 been discovered that the nomenclature of several was quite erroneous and 

 that some genera and species had been founded on young individuals of pre- 

 viously named forms. The preoperculum in early youth, as far as known, 

 is armed with three stout spines at the angle and smaller ones above and 

 below, the spinous dorsal is always developed at that period, and teeth are 

 also present. At a later period the spines of the preoperculum are absorbed 

 in the margin, while in some types the first dorsal becomes atrophied and is, 

 in several, represented by free and simple projecting spines, and 'at a still 

 later period the teeth are likewise lost. A single species of one such type 

 ( Trachynotus) has served at different stages of gowth as a representative of 

 three different genera, characterized by the condition of the spinous dorsal 

 and the dentition. 



The following table will enable the student to distinguish the several groups. 

 Although the genus Pomatomus Lac. (Temnodon Cuv.), is here retained in 

 the family, I am not certain that it truly belongs to it. 



The object of the present article is to correct the nomenclature of several 

 species, as well as to draw attention to the imperfection of our information re- 

 garding several others, especially the species of the subfamily of Centronotinae. 

 No one will deny that it is for the interest of science that the nomenclature 

 of the genera and species of animals shall be settled as soon as possible, and 

 it is hoped that the present communication will contribute to that desirable 

 end as far as the American species of Carangoids are concerned. Much, how- 

 ever, yet remains to be done. Although I have seen all the species enumer- 

 ated, with one exception,* specimens, from the eastern coast, of several 

 are not represented in the collection of the Smithsonian Institution. Those 

 desired species are the following: Decapterus punctatus, Carangus fatlax, 

 Blepharichthys crinitus, Trachynotus glaucus, Naucrates ductor, Zonichthys fas- 

 ciatus (young), and H. boscii. It is hoped that such deficiencies may be soon 

 remedied. 



* Halatractus boscii. 



[Sept 



