104 DIPLOPODA. 
O. palmensis. Brélemann, unfortunately, does not make his description comparative, and does not state 
clearly and concisely how this species may be distinguished from the others in the female sex. It appears 
to be most nearly allied to O. palmensis, but has the margins of the anal valves indistinctly compressed. 
The structure of the copulatory organ, however, serves to distinguish it at once from beth, for the distal 
portion of the posterior lamina of the coleopod is less rounded and expanded and bears externally on its 
anterior face a broad roundish process which diverges at an oblique angle from the external edge, and 
the latter is not produced into a definite anguliform or spiniform process. 
Number of segments 57-64. 
Length from 50 (¢) to 83 (2) millim., width from 3°30 ( ¢) to 4°80 (@). 
Hab. Costa Rica, La Palma, Carrillo, Caché (Biolley +). 
Fam. NANNOLENIDA. 
Divergent as this family appears to be from the Spirostreptide, the interval between 
them is to a great extent bridged by genera from various parts of the tropics. Physio- 
streptus, for example, described by Silvestri from Ecuador and made the type of the 
family Physiostreptide (Boll. Mus. Torino, xvili. no. 453, p. 14, 1903), has the 
copulatory apparatus constructed as in the Nannolenide and Pseudonannolenide, with 
the legs of the first pair in the male reduced to a single clawless segment in addition 
to the coxo-sternal plate; but the gnathochilarinm is constructed as in the Spiro- 
streptide. In the species described by Silvestri (op. cit. p. 9) as Lulomorpha chilensis, 
on the other hand, the copulatory organs have apparently distinct coleopods and phallo- 
pods as in the Spirostreptide, but the gnathochilarium is like that of Epinannolene, 
and, judging from Bollman’s description, the same is true of the North-American genus 
Cambala. 
Silvestri appears to regard the gnathochilarium as supplying characters of higher 
systematic value than the copulatory apparatus, for he associates the Physiostreptide 
with the Spirostreptide in the Spirostreptoidea, and refers Nannolene ( Epinannolene) 
to the Cambaloidea. But it may be doubted if this opinion is sound, in view of the 
eradational variation towards the Spirostreptoid type of gnathochilarium presented by 
various genera of Cambaloidea. Jor example, in the tropical Old-World ‘genera 
Glyphiulus, Trachyiulus, Cambalopsis, and Cambalomorpha (grouped as Cambalopside 
by Cook in 1895, and as Trachyiulide by Silvestri in 1896) the anterior portion of the 
promentum which separates the lingual lobes is narrow and not separated from the 
main part of the sclerite—that is to say, the gnathochilarium in these forms nearly 
approaches the mean between that of the Spirostreptide and that of the genera 
Cambala, Nannolene, Epinannolene, and Lulomorpha, the Cambalide of Bollman, in 
which the anterior portion is defined behind by a membranous line or joint; and in 
the latter the gnathochilarium similarly lies nearly midway in point of structure 
between that of the Cambalopside and that of the genus Pseudonannolene, the type of 
the family Pseudonaunolenide, in which the anterior part of the promentum is not only 
separated posteriorly but is also wider and longitudinally bipartite. 
