60 G. F. MATTHEW ON THE 



A variety occurs in wliich the rachis of the pygidium is longer, and the tubercle on 

 the middle lobe stretches across the lobe. 



The range oï Agnoslus pisifornm iu Sweden, according to Tnllberg,' is in the lower 

 part of the Olenus Zone, and this is confirmed by Brogger. The Paradoxides beds below 

 show no trace of it. But in the opposite direction it is represented by the variety socialis iu 

 the upper part of the Olenus beds. This variety has an enlarged posterior lobe to the rachis 

 of the pygidium, and TuUberg says is a transitional form leading to A. ci/clopi/ge, which 

 occurs a little higher up, just below the horizon of Parabolina spinulosa. Agiioslux pisijormis 

 and its derivative forms thus occurs in Sweden in beds that are equivalent to our Johan- 

 nian Division (Div. 2). 



If we suppose that A. pidformis originated from one of the Lougifrontes of the Paradox- 

 ides beds (e.g., A. intermedium), it will be noticed that the Acadian variety agrees more 

 nearly with these older Longifrontes than the typical form of A pisiformis (or its deriva- 

 tives) does. These considerations point to the base of the Olenus Zone as the place of the 

 Acadian variety. 



ANOMOCAEE, Angelin. 



In the ' Canadian Record of Science,' October, 1889, the writer described two species 

 of trilobites from Long Island, i\nder the genus Leptoplastus, Ang. Since then, having 

 obtained better material for these species, and having discovered in the St. John Basin a 

 typical Leptoplastus, the writer is of the opinion that these species should be referred to 

 Anomocare. 



Anomocare was described by Angelin in the following terms- : — 



Corpus oblongum, convexum, distincte longitudinaliter trilobum, crusta lœvi, exca- 

 vato-punctata, aciculata, vel alutacea tectum. 



Gipiii semilunare, sagittatum, margiue piano, sulcoque intramarginali, aut immargi- 

 natum ; anguli exteriores producti, acuminati. Frons subangusta, ovata vel oblougula, 

 marginem apicalem hand attingens, utrinque lineis impressis lobata, lobis decrescentibus. 

 Oculi majusculi, distantes medium versus frontis siti, loboque orbitali marginato prœditi. 

 Sutura facialis postice ab oculis oblique ad marginem basalem, auticeque ad marginem 

 apicalem decurrens. 



Tliorax constat e segmentis 10 — angustatis, sulco pleurico extrorsum evanescente 

 canaliculis ; apice obtusiusculus ; rachis angusta, convexa. 



Abdomen rotundatum, plerumque impressione intramarginali lata praeditum ; raehi 

 distincta, angusta, ante apicem scuti desinente ; costis lateralibus ante marginem evan- 

 escentibus.'^ 



• 'Agncstiis Arterna,' p. 9- -' ' Palœon. Scand.,' p. 24 Ins- 



'■'■ Body oblong, convex, distinctly trilobed lengthwise; covered with a smooth, excavato-punctate, acicnlate or 

 coreaceous crust. 



Head semicircular, arrow-shaped, margin flat, grooved within the margin, or witliout a marginal fold ; exterior 

 angles produced, acuminate. Glabella rather narrow, ovate or somewhat oblong, scarcely reaching the front mar- 

 gin, lobed on each side by impressed lines, the lobes decreasing. Eyes rather large, distant, situated opposite the 

 middle of the glabella, furnished with a marginal orbital lobe. Facial suture running backward from the eyes 

 obliquely to the basal margin. 



Thorax made up of 10 — segments narrowed, channelled with a pleural groove that vanishes toward the end, 

 and rather blunt at the end ; rachis narrow and convex. 



Pygidium rounded, usually provided with a broad intramarginal depression; rachis distinct, narrow, ter- 

 minating within the apex of the shield; lateral costse vanishing within the margin. 



