THE EURYPTERIDA OF NEW YORK 243 
The telson is furnished with small circular scales on the swollen basal 
part and with long spinelike scales on the remainder. 
TABLE OF MEASUREMENTS OF EUSARCUS SCORPIONIS (IN MILLIMETERS] 
>| 2 | » > a a 4 ao Se] Se |. 
2) 2|2la./2e| 2, (8 (2 |2a| 22] Fe | Es Ee] 2 [2,/25/ 38 | 3. 
| 2 ” 2 |S, ae) iS wa > Ti na =? 
= 3 8 \sa\S2| cm lcls3| 22/221 Es] Ze ise] 22 [sel esl ea | #3 
sla |slezies| Za levle7| as] ail 42] 23 les 28 |E3] 22] 22 | 4s 
a\Plzis2e7|& (2 le | Bs] Bs B42 | Bs ES) BR |e) <2] 28 | =F 
Pe} (= °o ‘= fone nord ~~ q 
e| 8 jel |A SR {a ] ae] as] s [a | ks 22| 82 |5 
Type specimen.....|....|.... (76); (120)| (32)}....]...... 84:112)(20):112). 0. fe fe cee de ee epee cee free eee epee 
Young specimen...-} 113} 182+]... .).....[.... ccf. ee ede eee [ee eee 23:35 54s ts) re rs 48.5) 5:18 14:7| 23:5 
Specimen A........].... 60 9| 44*| 87* 27| 37|...... 82:106)(19):108).. 2... fee pee cee fee ee elec ee cc fee eee ee epee eee 
Specimen B........} 328] (53)|....]....]....- (102)| (34)|33.5]...... 67:88] 17:88)........[....]...-0000- (146))11:(45)} (40):19) (62) 
Specimen C........|.... 56 9} 82) (117 (40)|...... 76:104}(18):104). 00... fee dee cc ec fee eee fee eens (47):(20)|..... 
Specimen D........]....] 62f]...., Up... foo... pepe eee. 99:(123)|22:(123)|........f..0.[..0. ee eee 205| 23:72! 61:25]... 
Specimen E........]....J..0. feeeedeceefecees (152+)} 63]... .|(39):30).......]....... (42):(77)|59-+- 5 ed oe 
Largest fragments | 
observel........]....]....f...-[. 06. 189+] 187+] 81) 75)......].......}.......f.......- L008, (49):(211)|.. 0. J. ..0.. 108+ 32 151+ 
* When marked by asterisk only the portion protruding from the carapace is measured. Approximate measurements are in parentheses. 
t Length of chelicera 44.5. 
Horizon and localities. Remains of this species have been found 
only in the Bertie waterlime quarries at Williamsville and Buffalo, N. Y. 
Observations. The relative size of some of the largest fragments 
indicates that E. scorpionis reached at least a length of four fifths 
of a meter or 2-3 feet and thus belonged to the larger members of the 
eurypterid fauna of the waterlimes. It attained at least half the size of 
the giants of this fauna, the two species of Pterygotus. 
Lacking the long and powerful pincers of those dangerous competi- 
tors, the principal or sole organ of defense and offense must have been 
the telson spine. In correspondence with this important function the 
postabdomen is so much extended that, with the telson, it greatly exceeds 
