BUFFALO SOCIETY OF NATURAL SCIENCES 223 



From the great mass of detail which it has been necessary to give, 

 we are at length able to reach two conclusions: (i) Stylonurus from 

 its earliest appearance in the Normanskill beds (Black River or Basal 

 Trenton) to its last appearance in the Chemung was an inhabitant of 

 the rivers of Appalachia; (2) Dolichopterus also first known in the 

 Normanskill, but so far not known from beds later than the Bertie, 

 is most rationally to be considered as restricted in its habitat to the 

 rivers of Appalachia, although the paucity and the condition of the 

 specimens make this conclusion not absolutely certain. 



This much being determined, we may consider the remaining fau- 

 nas which have been found in sediments which from other lines of 

 reasoning are recognized as coming from Appalachia. In the Sche- 

 nectady shales eleven species are recorded, of which four have already 

 been discussed. Of the remaining seven, Eurypterus ruedemanni and 

 E. pristinus are represented each by a single carapace neither of which 

 is of use in comparisons, and the same may be said of the doubtfully 

 determined form Euscarcus (?) longiceps of which a few incomplete 

 carapaces are known. Nine carapaces of Eusarcus triangulatus 

 have been found, and these Clarke and Ruedemann state "have in 

 common the broad, short, sub triangular form; and the forward posi- 

 tion of the marginal lateral eyes bears a close resemblance to the cara- 

 pace of E. scorpionis from the Bertie waterlime" (39, 258). Yet the 

 figures, measurements and descriptions of these two species given by 

 the above mentioned authors do not bear out this "close resemblance." 

 In reference to E. triangulatus they say that the carapace is "twice 

 as broad as long (length of type, 20 mm., width 43 mm.)" and of E. 

 scorpionis they say that the carapace is about "as broad as long" 

 (p. 234), while in the measurements which they give of this species 

 the length is to the width (in millimeters) as 18: 22, 60: 66, and 

 56: 59, respectively. For comparison I give outline drawings of the 

 restoration of the carapace of E. scorpionis and of the actual carapace 

 of the type of E. triangulatus (Figs. 19a and b). One of the common- 

 est species in the Schenectady shales is Hughmilleria magna, known 

 from a number of carapaces, some abdomina, and a half complete in- 

 dividual. "This exhibits a form of the preabdomen corresponding to 

 H. socialist but the swimming leg is "relatively longer than that of 

 H. socialis" (Pittsford) (39, 342). Several detached body rings have 

 been found regarding which Clarke and Ruedemann say: they "ex- 

 hibit a type of ornamentation, consisting of transverse lines near the 

 anterior margin, known to us only in H. shawangunk, the Otisville 



