168 NEW YORK STATE MUSEUM 
tral side [pl. 8, fig. 3] is ornamented with closely arranged semicircular 
to semilunar scales, largest and most prominent in the middle anterior 
region of the operculum, otherwise rather faint. 
Ontogeny. Eurypterus remipes has not yet afforded any 
growth stages as young as those of species from Otisville. The smallest 
specimens are already of neanic age. Hall figured an example [1859. v. 1, 
pl. 80, fig. 1] which without the telson spine, measures but 18 mm. An: 
outline drawing [text fig. 33] and photograph [pl. 4, fig. 1] of this speci- 
men are here reproduced, and also the drawing of another small indi- 
Figure 33 Outline camera drawing of 
. Gi 
young of Eurypterus remipes. x3. 
The same specimen is reproduced on Figure 34 Another very young specimen of 
plate 4, figure 1 _ the same species. x3 
vidual [text fig. 34] given by Clarke in Zittel-Eastman, Text-book of Palae- 
ontology, 1896, figure 1420. In the explanation of these figures Clarke 
pointed out the strongly anterior position of the eyes, relatively large size 
and length of the swimming legs and abrupt posterior contraction of the. 
abdomen. The paucity of abdominal segments in figure 33 proves on 
investigation to be only apparent and due to the forcing of the posterior 
abdominal segments under the anterior. This secondary contraction of the 
body, apparently but accidental, or incidental to the process of molting, 
is also observed in some other young individuals. It is the principal cause 
_ of the contracted appearance of the abdomen. 
