WATERLIME GROUP. 407* 



Enrypterus microplithalmus (n.s.)- 



Plate LXXX A. Fig. 7. 

 Cakapace semioval, straight behind, more than two-thirds as long as wide ; 

 outline regularly curved. Eyes small, oval, placed much within the 

 margins : distance between the eyes scarcely greater than between 

 the eye and the outer margin of the carapace. First joint of the thorax 

 narrow. 



Fig. 7. The carapace, natnral size, preserving a part of the first joint of the thorax. 

 Geological position and locality. In the tentaculite limestone, associated with 

 Spirifer plicatus; from a loose fragment near Cazenovia. The associate fossil is 

 clearly determiuate of the geological position of this specimen. 



Eurjptenis lacustiis. 



Platk LXXXI. Fio. 1 - 11 ; Plate LXXXI A. Fig. 1 ; Plate LXXXI B. 

 Fig. 1 - 5 ; and Plate LXXXIII B. Fig. 3. 



Eioypterui lacuttri* : Hari.an, Trans. Geol. See. Pennsylvania, Vol. i, pa. 98, pi. v : 1834. 



— — : Idem, Med. and Phys. Researches, p. 297. 



— — : HiBBEET, Trans, of the Royal Society of Edinburgh, Vol. xiii, pi. xii. 

 £. rtmipes : Rcemrr, Dunker und Von Meyer, Palseontographica, Vol. i, p. 18. 



— — : PiCTET, Traits de Paleontologie, Tome ii, pa. 29, pi. xlvi, f. 14 : 1853. 



— — ; Bronx et Rcemer, Lethea, 3d edition, 1854, vol. ii, pa. 666, pi. ix', f. 1. 

 Not E. remipes of Dekat. 



Not £. lacitstris, Salter, Quart. Journ. Geol. Soc. London, Vol. xv, p. 235 : 1859. 



Cakapace broad, somewhat straight in front and upon the sides, about 

 two-thirds as long as wide. Eyes depressed, reniform or subelliptico- 

 reniform, concentrically striated. Body robust, ovato-lanceolate : tho- 

 racic portion a little wider than the carapace, and perceptibly narrowing 

 at the fifth and sixth articulations ; below which, at the commencement 

 of the abdominal portion of the body, there is a marked contraction. 

 The first seven joints from the head are of nearly equal length and 

 extremely transverse, being seven or eight times as wide as long : the 

 posterior articulations are subquadrate, and the one preceding the tail- 

 joint is longer than wide. The tail-joint is prolonged into a strong 

 triangular spine, which is somewhat obtuse at the extremity, and the 

 angles finely serrate. 



