POLYLEPISCUS. 155 
1. Polylepiscus stolli, sp.n. (Tab. XII. fige. 3-3d.) 
2. Colour fairly uniformly yellowish-brown, with legs, antenns, and thickened margin of keels clearer 
(when living probably dark brown or black, with the antenna, legs, and keel-margins yellow). rst tergal 
plate smooth, very lightly sculptured quite at the sides, nearly as wide as the second; its anterior border 
nearly evenly convex; a very short lateral border, the posterior angle subrectangular, and the posterior 
border directed obliquely forwards and outwards externally. Dorsal area of 2nd, 3rd, and 4th almost 
smooth mesially, with polygonal subtubercular sculpturing upon the keels; from the 5th to the middle 
of the body the sculpturing becomes gradually more distinctly defined as three transverse rows of low 
smooth polygonal areas, which on the keels become more tubercular. In the posterior half of the body 
these rows become less regular, more broken up, so that as many as four rows of more irregularly 
shaped areas are traceable; on the upper side of the 18th the sculpturing consists mostly of longitudinally 
elongate tubercles; on the 19th the sculpturing is confined to the posterior half and consists of 
anastomosing longitudinal grooves. eels nearly horizontal; the anterior angle widely rounded, less so 
on 2nd and 3rd, anterior border serrulate from about the 6th; posterior border concave, distinctly 
serrulate from the 5th; posterior angle acute and becoming gradually more and more produced and 
spiniform from before backwards; from about the 7th the spiniform process, which is very long, slender, 
and lightly incurved on the posterior segments, surpasses the posterior border of the median portion of 
the segment; lateral border fairly evenly and lightly convex on the poreless segments, except the 2nd, 
3rd, and 4th, which are lightly emarginate, but on the pore-bearing segments there is a distinct notch- 
like emargination marking the position of the pore; margins of all the keels moderately thickened and 
uptilted posteriorly ; the thickening more marked upon the pore-bearing segments. Pores completely 
lateral even upon the 18th and 19th segments ; keels of the 18th strongly acute but hardly spiniform ; 
keels of the 19th markedly angular, with apex blunt. Caudal process with lightly convex lateral 
borders, rather more strongly convex posterior border, and rounded angles. Anal sternal plate with its 
posterior border markedly convex between the two small tubercles. Lateral area of segments granular ; 
lower side of keels smooth, at least externally. Terminal segments of legs bearing stout sete, not short 
slender spines. 
Length, 2, 65 millim., width 10. 
Hab. N.W. Guatemaua, Cholhuitz (Séol/). 
Although resembling P. heterosculptus, Carl, in its rounded anal sternal plate and 
strongly spiniform posterior angles to the keels, this species is quite distinct in having 
smaller keels with the anterior border more abruptly recurved, in the absence of the 
granulation from the dorsal area, the smoothness of the median area of the anterior 
segments, the lateral position of the pores upon the 18th and 19th keels, the more 
distinct serrulation on the anterior and posterior borders of the keels, the less squared 
caudal process, &c. 
2. Polylepiscus actzon, sp.n. (Tab. XII. figg. 2-2.) 
@. Colour brown, the external half of the keels yellow, legs brown (head and segments 1-4 missing). The 
entire dorsal surface rugose, covered closely with low anastomosing granules and small tubercles, 
amongst which the three transverse rows of polygonal areas are easily detectable, except on the 17th to 
19th segments, where they become obsolete and lost amougst the granulation; a few scattered larger 
tubercles, showing obscure arrangement in three transverse rows, visible here and there upon the lateral 
slope of the dorsal and the adjacent portion of the keels; upper side of the 19th granular and sulculate. 
Keels large, horizontal; anterior border of the 6th lightly convex, posterior border lightly concave. 
From the 6th backwards the anterior border becomes more and more convex and prominent at the base 
and the posterior border very gradually straighter and more in line with the posterivr border of the 
tergal area, and at the base more and more thickened and shouldered, the shoulder-like thickening quite 
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