84 NEW YORK STATE MUSEUM 



of Oesel ; the genus P ® e u d o n i s c u s Nieszkowski. This 

 peculiar, eyeless, semi-trilobitic merostoine has indeed been 

 seen before in but a single species, of which we have record of 

 only two examples, both incomplete, the one figured by 

 Nieszkowski and the same with an additional' fragment given by 

 Friedrich Schmidt. 



In recent collections made from the Eurypterus dolomites of 

 the town of Litchfield, Herkimer countj^ we have acquired 

 another representative of this peculiar crustacean, at a horizon 

 lying somewhat but not far above the gypsum beds of the 

 Salina formation. It has also appeared in collections made by 

 C. J. Sarle from black shales and interlaminated dolomitic slabs 

 from beneath the gypsum beds in Monroe county, and from this 

 latter horizon, which is one not before recorded in the New 

 York paleozoic, the representation of the creature embraces two 

 entire and admirably preserved individuals, and in addition 

 thereto a number of head-shields. - In the latter locality the 

 Pseudoniscus is associated in the black shales with a 

 number of other Crustacea, a Pterygotus^ an Euryp- 

 terus and a pterygo'toid genus which will have to receive a 

 distinct generic designation, all of which are now under study 

 by Mr Sarle. Some of the phyllocarid Crustacea described here- 

 with under a separate caption, are also from the same black 

 shales at this low and heretofore unrecognized horizon for such 

 crustacean fauna. The thin dolomite slabs which lie in these 

 shales and into which some of the shale fossils extend, carry 

 Leper ditia scalaris Jones and a pterineoid like P t e r - 

 inaea subplana Hall. The Litchfield specimens occur with 

 the usual well-known Eurypterus fauna of the upper Waterlime, 

 Eurypterus remipes, Pterygotus macro ph - 

 thalmus. Dolichopterus mac r o c h r i u s, etc. 



Nieszkowski described the genus Pseudoniscus in 1859^ 

 The original of Pseudoniscus a c u 1 e a t u s Niesz., a 

 specimen found by Dr Friederich Schmidt in 1858, consisted of 



^Zusatze zur Monographie der Trilobiten der Ostsee-provinzen: Archiv 

 fur Naturkunde Liv-, Est- und Kurlands, ser. 1, 2: 381, pi. 2, fig. 15. 



