TRACKS AND TRAILS. IC>5 



by a species of Dikeloccphalus, possibly by D. hartti, which occurs both north and south of the 

 Adirondack^. In a recent paper, Burling (Amer. Jour. Sci., ser. 4, vol. 44, 1917, p. 387) 

 has argued that Protichnites was not the trail of a trilobite, but of a "short, low-lying, more 

 or less heavy set, approximately i2-legged, crab-like animal," which had an oval shape, toed 

 in, and was either extremely flexible or else short and more or less flexible in outline. 

 This seems to describe a trilobite. 



Cliinactichnites, the most discussed single trail of all, has also been ascribed to trilo- 

 bites, by Dana (Manual of Geology, 1863, p. 185), Billings (1870, p. 485), and Packard 

 (Proc. Amer. Acad. Arts and Sci., vol. 36, 1900, p. 64), though less frequently than 

 to other animals. The latest opinion (see paper by Burling cited above) seems to be against 

 this theory. 



Miller (1880, p. 217) described under the generic name Asaphoidichnus two kinds of 

 tracks which were such as he supposed might be made by an Asaphus (Isotclus). In re- 

 ferring to the second of the species, he says : "Some of the toe-tracks are more or less 

 fringed, which I attribute to the action of water, though Mr. Dyer is impressed with the 

 idea that it may indicate hairy or spinous feet." The type of this species, A. dyeri, is in the 

 Museum of Comparative Zoology, and while it may be the trail of a trilobite, it would be 

 difficult to explain how it was produced. 



Ringueberg (1886, p. 228) has described very briefly tracks found in the upper part 

 of the Medina at Lockport, New York. These consisted of a regularly succeeding series of 

 ten paired divergent indentations arranged in two diverging rows, with the trail of the pygid- 

 ium showing between each series. The ten pairs of indentations he considered could have 

 been made by ten pairs of legs like those shown by the specimen of Isotelus described by 

 Micklebo rough, and the intermittent appearance of the impression of the pygidium suggested 

 to him that the trilobite proceeded by a series of leaps. 



Walcott (1918, pp. 174-175, pi. 37-42) has recently figured a number of interesting 

 trails as those of trilobites, and has pointed out that a large field remains open to anyone 

 who has the patience to develop this side of the subject. 



