28 | NEW YORK STATE MUSEUM 
was sharply bent and the angulation has produced a distinct protrusion 
on the dorsal side of the last segment [pl. 75]. 
4 The scales are not found on the telson spine, except the anterior 
swollen portion where the extensors and flexors were attached, nor on 
the broad, solid oarplates of the swimming legs, while they are present 
on the leg segments, frequently in distinct longitudinal rows which in some 
cases develop into regular continuous entapophyses on the inside of the 
integument, as in the powerful arms of Dolichopterus [pl. 43]. 
5 On the postoral lip (metastoma) the scars are most strongly 
developed on the side that is turned toward the body and held by 
muscles. | : 
6 The prevailing form of the scales is that of a V or a crescent point- 
ing backward, and this shape, together with the fact that the integument 
is distinctly thicker and darker along the edges of the scales, is indicative 
of their function, since the muscle scars here, as among mollusk shells, 
are marked by their thickened edges. Forms with thicker integument, 
as Eurypterus microphthalmus, do not exhibit any scaly 
sculpturing on the outside. 
» The scales are well differentiated from the tubercles which are 
scattered among them [see test of Eusarcus, pl. 35, fig. 4] and on those 
parts where the thickness of the integument prevents the appearance 
of scales over the surface, as on the carapace, these tubercles alone are 
observed. Similarly the serrations of the edges of the rudder plate of the 
swimming legs, of the epimera of the abdominal segments and of the telson 
are independent of scales. But it appears that the spinules on the dorsal 
crust originate from scales, we surmise from a lengthening of the point 
of the angle of the V. In Eurypterus remipes, lacustris 
and pittsfordensis, as wellas fischeri, but a single trans- 
verse row of such spines is developed on each segment. In E. remipes 
the longitudinal series of scales on the postabdomen over the intestine 
show a strong tendency to develop into overlapping spinules and in the 
Carbonic subgenus Anthraconectes all scales possess this tendency. 
