been well nigh 15 inches. The later and common Hamilton species, 

 H. DeKayi, attained no extravagant size though frequently large, e. g. 

 the enrolled individual figured on plate IV (op. cit.'), the largest entire 

 specimen reported, which is about 9 inches in length; some large 

 fragments indicate that the animal was sometimes as long as 11 

 inches. 



The size attained by some of the Devonian species of Dal- 

 MANiTES and their immediate predecessors was marvelous. The 

 pygidium of D. micrurus figured in the Palaeontology of New 

 York, Volume III, page 359 (there given as D. j)leuroptyx), indicates 

 an individual at least 11 inches in length, and there is reason to 

 believe that the Lower Helderberg species, D. nasutus and D. tridens, 

 attained a size fully as great. Most remarkable however is the great 

 pygidium of D. myrmecophorus of the Corniferous limestone, figured 

 upon plate XV of Volume VII {op. ciL), which from the restoration 

 there given, made from careful comparative measurements, would 

 imply an individual 16 inches long. 



An interesting feature of the early Devonian trilobitic faunas is 

 the reappearance of Calymene in the Schoharie grit and Corniferous 

 limestone, a fact which has been duplicated by the recent 

 description by Dr. Oehlert of a large species (C. reperta), from 

 the lower Devonian of Saint Malo in Angers. The American 

 Devonian species, G. plazys, is not only the latest but the largest known 

 representative of the genus, aud for a group which at its maximum 

 development in species and individuals in the Silurian, rarely attained 

 considerable dimensions, the proportions reached by G. plaiys are 

 especially noteworthy. The entire individuals on plate 1 of Volume 

 VII of the Palaeontology show this, and the restoration accompanying 

 a very large pygidium on plate xxv, if accurately drawn, indicates 

 that a length of upward of eight inches was sometimes attained by 

 the species. 



No larger or more extravagantly ornamented trilobite than the 

 Terataspis grandis, Hall, is known. This giant of its race has left 

 fragments of its test in the Schoharie grit of eastern New York, and 

 in the commingled Schoharie and Corniferous faunas of the Province 

 of Ontario. A very complete illustration and discussion of its differ- 

 ent parts, are given in Volume VII of the Palaeontology (p. 73, pis. xvii, 

 sviii, xix), and from these one readily obtains an idea of the structure 

 of the cephalon, thorax and abdomen, the free cheeks alone being 

 there unrepresented. There is, however, a very large free cheek in a 

 fragment of Schoharie grit in the collection of the American Museum 

 of Natural History, which in all probability belongs to this species. 



