98 DIPLOPODA. 
and finely punctured and striate. The posterior portion of the anterior part of the segments similarly 
but a little more finely sculptured. Pores beginning on the sixth segment. Anal segment with its tergal 
plate longitudinally flat above, not covering the summit of the valves, which have compressed margins ; 
sternal plate lightly convex along its posterior margin. Antertor lamina of coleopod short, its distal 
end narrowed and rounded. Distal end of posterior lamina elliptically rounded, antero-posteriorly com- 
pressed, and armed externally with a slender spiniform process, which projects obliquely downwards 
and outwards. 
9. Antero-inferior angle of first tergal plate slightly less prominent ; exposed segment of mandible smaller. 
Number of segments 62-64 (9), 65 (¢). 
Length @ 82 millim., width about 6; ¢ 96 millim., width 6. 
Ilab. Mexico, Teapa in Tabasco (H. H. Smith). 
5. Orthoporus amulensis, sp. n. (Tab. VIII. fig. 5.) 
? Spirostreptus fraternus, Sauss. (cf. infra). 
$. Colour (in alechol) dark brown, the segments obscurely banded, the anterior part being blackish and the 
posterior ferruginous ; anal segment blackish ; legs and antenne yellowish. 
Head and first tergal plate smooth. Inferior portion of the first plate not markedly incurved, marked with 
about four ridges, the upper of which is not posteriorly tubercular. The anterior angle rectangular, 
subacute, the posterior obtusely rounded. Lower margin of basal segment of mandible emarginate, the 
posterior lobe acute. The crests of the succeeding segments fine, narrower than the spaces between 
them. Posterior half of segments thickly punctured, finely ridged in front behind the sulcus; in front 
of the sulcus the anterior part is finely punctured, so that the two areas of the segments are marked off 
from each other by the difference in the coarseness of the sculpturing ; the distinction, however, is less 
marked than in O. striatulus and more marked than in O. cordovanus. Pores beginning on the sixth 
segment. Anal tergal plate longitudinally convex above; obtusely rounded posteriorly and not covering 
the summit of the valves, which have compressed margins ; anal sternal plate obtusely rounded. Anterior 
lamina of coleopod long, its inner distal angle slightly produced; distal end of posterior lamina laterally 
compressed, and produced externally into a short, blunt process. 
Q a little larger than ¢, with infero-anterior angles of the first tergal plate obtusely rounded, and the inferior 
édge of the basal segment of the mandible emarginate. 
Number of segments 77-79. 
Total length of adult from about 80 to 90 millim., width 4 to 4:5. 
Hab. Mexico, Amula in Guerrero (//. H. Smith). 
This species may prove to be the same as the one described by de Saussure as 
Spirostreptus fraternus, as is forcibly suggested by the dimensions and the number 
of segments. 
6. Orthoporus cordovanus, sp.n. (Tab. VIII. fig. 3.) 
? Spirostreptus otomitus, Sauss. (cf. infra). 
6. Prevailing colour (in alcohol) olive-brown, with the posterior border of the terga ferruginous; legs and 
antennee yellowish. . 
Head and first tergal plate smooth. Lateral portion of first plate not noticeably incurved, marked with four 
‘strong grooves and ridges, the latter, however, not showing tuberculiform enlargements on the posterior 
edge; posterior angle obtusely rounded; anterior angle rectangular and subacute. Inferior edge of basal 
segment of mandible emarginate, but the posterior lobe of the emargination not produced below the level 
of the anterior, and not rounded but subacute. Pores beginning on the sixth segment. Exposed area of 
_ median portion and the posterior portions of segments finely and uniformly punctulate and striolate. 
Anal valves compressed ; anal sternal plate widely and obtusely rounded, not acute. 
