146 DIPLOPODA. 
but sharpish teeth, which, however, vary in size upon different segments, but are never so large as in 
P. montivagus ; the pore-bearing keels show a shallow emargination or a toothless smooth area opposite 
the pore which is quite close to the lateral edge; the keels without pores generally exhibit a lateral 
notch, which is visible even on the 4th segment. The dorsal surface closely granular, with the three 
rows of tubercles just traceable on the middle of the body, and more distinct at its anterior and posterior 
ends, especially upon the lateral slope of the segments. Lateral border of the keels of the 2nd convex, 
tubercularly toothed, with the posterior angle more convex and less prominent than the anterior ; first 
tergal plate with tubercles extending nearly round its circumference, slightly depressed behind its 
anterior border, which is evenly convex to the blunt lateral angle. Head without distinct frontal 
tubercles, such as are seen in P. bivirgatus and P. tristani. Sternal area, from the 4th to the 7th, 
with a distinct tooth-like tubercle at the base of each leg; from the 7th backwards these tubercles 
gradually die away; sterna of 5th and 8th longitudinally and transversely sulcate ; those of the median 
and posterior areas markedly notched laterally and angularly excised posteriorly, the posterior notches 
being more or less coxiform; all the sterna granular and generally wrinkled. Caudal process short, 
widely rounded. Anal sternal plate wide, with rather large tubercles. 
g. Smaller than the 9, but with the keels relatively larger and more strongly excised. No distinct 
tooth on the sternal area of the 4th; sternal area of 6th and also of 7th behind the phallopods also 
untoothed. Phallopods stout, crossed, gradually curved upwards at the end, the auxiliary branch sickle- 
shaped, attenuated and pointed; seminal stile relatively long and showing a distinct but not strongly 
pronounced sigmoid cnrvature. 
Length, 2, 75-80 millim., width 11-12. 
» oo, 55-65, » 15-8. 
»  & (type), 55 29 » 12. 
Hab. Costa Rica (Rogers), Rancho Redondo 2000 metres (Biolley '). 
TIRODESMUS*. 
Tirodesmus, Cook, Brandtia, xii. (1896). 
Keels, except at the anterior and posterior ends of the body, very large, laterally narrowed owing to the 
oblique backward inclination of the anterior border, the lateral border, where defined, only about halt 
the length of the base of the keel, the anterior and lateral borders forming a continuous arch broken 
only by the teeth marking the commencement of the lateral edge; upper surface of metazonites studded 
with coarse comparatively widely spaced granules, amongst which the three rows of tubercles, especially 
the posterior, stand out like pearly pustules; both anterior and posterior borders of the first tergal 
plate raised and studded with coarse pearly tubercles; the plate markedly hollowed longitudinally in 
the middle and transversely behind the anterior border. Antenne long, second to fourth segments much 
longer than their distal thickness, the second much longer than the first. Leys long and slender; third 
segment at least twice as long as the width of the sternum, sixth segment tapering to a point which is 
scarcely wider than the base of the long slender claw. Phallopods not arcuate and not upcurled apically, 
projecting straight forwards, distally spatulate, with the seminal stile directed forwards. Sternum ot 
the sixth not excavated, as high behind as in front. 
Type, 7. fimbriatus, Peters. 
Distribution. Central and South America. 
1. Tirodesmus biolleyi. (Tab. X. figg. 9-9 6.) 
Platyrrhacus biolleyi, Carl, Rev. Suisse Zool. x. p. 658, t. 11. figg. 67, 68 (1902)*; Brdlemann, 
Ann. Soc. Ent. France, Ixxiv. p. 841 (1905) *. 
Colour black or dark brown, with the extreme margin of the keels and the larger dorsal tubercles yellowish-white. 
* Omitted from the ‘ Zoological Record. 
