612 THE POPULAR SCIENCE MONTHLY. 



to discard barbarous names, and, when a species becomes the type of a 

 new genus, he would retain the former specific name as the generic ap- 

 pellative. He objects to the use of small initial letters for substantives 

 borrowed from persons or places, to the uniform restriction of family 

 and sub-family terminations to idai and inm, and strongly condemns 

 the proposition that the name of the original propounder of a species 

 should be retained when the species is transferred to a different genus. 

 He likewise condemns those who would change the authority for a 

 genus when the name is changed through faulty orthography, and 

 censures the use of vernacular names in scientific works to the ex- 

 exclusion of the systematic ones. 



The " Fossil Fishes " was now approaching completion, but, in con- 

 sequence of additional material, Agassiz determined to publish a sup- 

 plement; and accordingly there appeared, in 1844, the "Fossil Fishes 

 of the Old Red Sandstone." It was accompanied by an atlas of 

 thirty-nine folio plates illustrative of the seventy-six species described. 

 The author, after discussing the relative rank of the members of the 

 various classes of the animal kingdom, and showing how closely the 

 time of their appearance on the earth corresponds to their relative 

 standing in their respective classes, announces the conclusions to 

 which a study of the fishes of the Devonian system had led him. 

 These fishes actually represent the embryonic age of the Reign of 

 Fishes, undergoing "phases of development analogous to those of the 

 embryo, and similar to the gradations which the present creation 

 shows us in the ascending series it presents when viewed as a whole." 

 The members of the five families ^Jiose species he describes, are char- 

 acterized by the absence of distinct vertebrae, the apophyses resting 

 on the spinal cord, and by the absence of ossification in the internal 

 case of the cranium. In these characters, as well as in the peculiar 

 development of the vertical fins, the heterocercal tail, the flattened 

 form of the head, and inferior or sub-inferior mouth, we see peculiari- 

 ties of structure common to the embryo and the lower forms of exist- 

 ing as well as paleozoic fishes. This affords us a key to the relative 

 rank of these fishes, for we find the Cephalaspides, which recede most 

 from the existing forms, confined to the Devonian. The Sauroids, 

 which are represented only by a particular group — the Dipterians — 

 are likewise confined to the Devonian. The Acanthodians become 

 extinct at the end of .the Chalk, while the Cestraciontes persist to the 

 present epoch. The same year Agassiz also read before the British As- 

 sociation a " Report on the Fossil Fishes of the London Clay." 



Of all Agassiz's investigations, perhaps none made his name more 

 popularly known than his studies on glaciers— studies which were pur- 

 sued through a long course of years, and conducted with the same 

 painstaking care that had heretofore characterized all his labors. 



About the year 1834, M. Charpentier advanced the theory that 

 the erratic blocks, and certain dikes of peculiar shape found in the 



