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252 NEW YORK STATE MUSEUM 
a fairly continuous series of later growth stages, the first two of which 
correspond in size to Claypole’s E. newlini, the last two to his 
E. ingens. In the introductory remarks we have already given reasons 
for uniting the two names. These can be briefly restated as consisting in the 
absence of the distinguishing characters cited by Claypole and in the agree- 
ment of the dimensional proportions in the smaller and larger individuals. . 
There appear to exist a few actual differences between the smallest and 
TABLE OF MEASUREMENTS OF EUSARCUS NEWLINI 
2/2) 2]. le la le la | es. leelae], [EB le 
A Re g 8 P| SS |SHhlSaBl/2 ISB |B 
s |2|2| 83) #2/en|2_|3_| 32 |Fe| 38 | bs 28.| Fe 
A § o uw OF | = wo | 22 1 Ce 3S ye |yalesg Bs E43 
= m= | os Ss ls] Sw l/s 8] 68 s2 | a8] 3% 6 (gSE| s 
a ° a 3 rok| a5 a am ad 80 | ct & £2 a2 6 pe 
= | S| 2) 28/8/27 |& |B | BS | Bs) S23] Fis") S 
2 Q en aa DB 
218 {e2 [FR [8 JA |e [Ss | Be | as] Ss g2 [8 
(48:) (24:) 44: 
Original drawing of E. newlini! .... 264; 50+] — — |72+ 2) 1104+) — — (94)} —-]| — 122] (27) 3 12 
, 7 (148:) 80:| 108 
Original drawing of IE. ingens4..... 636] — — — | 164+] (188) 72 80 (228)} — _ 237 4) 24 
Specimen A (pl. 37).............6-- — 45 50, — 70| 107 28 40 50:89, — — — — _ 
Specimen B...............00- ee eee 270 58 68 14 80 116 28 38] (57):96} — _ 112} 34:29) 43:12 
Specimen C (pl. 38)...........0000. 400+} — _— — — (194)| (51) 73} (93):(145)| — —_ —_ 62:48; — 
Specimen D (pl. 39).............0.. (364+) 103 108] (18-20); — — ff — — 110:190) — _ _ —_ — 
Parentheszs imply approximate measurements. 
1Claypole records ©. newlini as measuring 10-12 inches. The original drawing measures 5} inches and can therefore be safely 
considered as being a one half reduction. 
2 The legs are measured to median line of carapace. Measurements too small from figures since full length of spines not drawn. 
3 Drawing obviously not reliable as to this proportion. 
4 Claypole gives as the length of the type 24 inches, but from the scale appended to the original drawing the original would measure 
considerably less. The drawing measures 6} inches. We assume therefore that it is reduced to one fourth and that the scale is Incorrectly drawn. 
largest specimens, which can be more plausibly explained as growth dit- 
ferences rather than varietal distinctions. There are the somewhat greater 
width of the carapace and more convex lateral margin, the greater thick- 
ness of the walking legs and swimming legs in the largest specimen, all of 
which combine to give the latter a more robust and less agile appearance. 
The same age difference we have observed in other eurypterids, as has 
‘been noted more fully in another place. 
