CRUSTACEA. 63 



Observations. The Calymene macrophtalma of Brongniart (Crustaa s Fossiles, p. 

 15, pi. i, figs. 4, 5. 1822) embraced much heterogeneous material, ami included 



a specimen which is now referred to Dalmanites anchiops. Two of the diverse 

 forms mentioned by Brongniarl were from unknown localities in America; one 

 of these was a plaster cast made from the specimen which subsequently served 

 as the type of Asaphus laticostatus of Green. Of the others, one form {lab. cil., 

 fig. 5), is the Calymene macrophthalma of Murchison, Phacops Brongniartii of Port- 

 lock, and the Pharops latifrons of Burmeister; the other is the Phacops macrophthal- 

 mus of Burmeister. The Asaphus Welherelli, Green, which lias Keen regarded 

 by Burmeister (Organiz. der Trilob., p. 90) as probably a young individual of 

 Phacops anchiops, was undoubtedly an imperfect specimen of Dalmanites limuhrrus, 

 Green, from the Niagara group. 



Dalmanites anchiops and its varieties show a divergence from typical forms 

 of the genus Dalmanites (D. Hausmanni, D. pleuroptyx, etc.), in the coalescence of 

 the first and second pairs of tin' glabellar lobes, a feature which places it under 

 the group Chasmops of McCoy. In the typical species of Chasmops (Phacops) 

 conicophthalmus, Sars and Boeck; Phacops macrurus, Sjogren, these united lobes 

 are large, and upon the dorsal surface give no apparent evidence of the obso- 

 lescent second glabellar furrows. D. anchiops in its usual condition of preser- 

 vation as casts of the inner surface of the test, shows traces of these furrows, 

 hut when the crust is retained, or upon casts of the dorsal surface they are 

 quite obsolete The small basal or third glabellar lohes are usually quite 

 distinctly separated from those in front, hut occasionally show a tendency to 

 coalesce with the others and form a single lobe on each side. In some species 

 of Dalmanites (Phacops Lopatini, Schmidt, and Phacops Sibericvs, Schmidt), this 

 coalescence is complete, and for such variations the sub-generic term Monorakos 

 has been recently proposed (Schmidt. Hull, de I'acad. imp de sciences de St. 

 Petersb., vol. xii, p. 417. 188G). 



Distribution. Dalmanites (Chasmops) anchiops: Oriskany sandstone. Walpole, 

 Province of Ontario, in association with Phacops cristata, var. pipa, Streptorhynchus 

 (Orthis) hipparionyx, Spirifera arrecta, Rensseleria ovoides. Upper Helderberg 

 group. Abundant in the Schoharie grit, in the town of Knox and vicinity 



