IV. 
ON THE XYODESMIDi®, A NEW FAMILY. 
Under this name may be arranged several genera the pertinent 
affinities of which have thus far not been indicated. For example, 
Dr. C. O. von Porat has identified Polydesmus erythropus Lucas* 
from Kamerun, referring it first to Oxydesmust and then to Parades- 
mus+. My opinion is that it belongs to neither of these genera, and 
that the Kamerun species is not that described from Liberia by Lucas. 
It is proposed to name this new form, and to found on it a new 
genus, the binomial to be Scaptodes 7 nus porati. There is in the Ber- 
lin Museum a specimen from Kamerun belonging to an evidently 
related, though distinct genus. The dorsum is strongly and evenly 
convex, and densely and finely granular ; the lateral and posterior 
margins of the segments are distinctly and closely serrate-dentate ; 
the pores are borne on a small, distinct, lateral callus on the usual 
segments. For this the name Thymodesmus is proposed ; the type 
species, Th. pulvmar^ is known only from a female specimen with 19 
segments ; it measures 23 mm. by 5.25 mm. These genera, together 
with Diaphorodesmus Silv., Cryptoporus Prt., and Xyodesmus 
Ck., constitute the African division of the family. There is some re- 
resemblance to the Oxydesmidae in the broad anal segment, but 
even this is, if closely observed, very different from that of any known 
member of the Oxydesmidae. The location of the pores is also very 
different, while the special development of the tubercles of some of 
the anterior segments is a character shared only by the Oxydesmidae. 
In South America are three or four genera in all probability more 
related to each other and to the above African forms than to other 
American families. I have, for instance, before me the types of 
Trachelodesmus and Thymodesmus, and the relationships, while by 
no means close, appear to be substantial. There are two other South 
American genera of Xyodesmidae. Hypodesmus is nearly related to 
Trachelodesmus, and is founded on Trachelodesmus constrictus (Ptrs). 
The other is established for Rhachidomorpha alutaeea (Ptrs). To 
* Lucas, Myriapodes du Gabon, Thomson’s Archives Entomologiques II, 
p. 442, 1858. “Patrie; cote de Malaguette.” This is the “Grain” or “Pepper 
Coast,” a name formerly applied to Liberia. 
t Porat, Bih. K. Sv. Vet.-Ak. Handl, XVIII, No. 7, p, 22, 1893. 
tibid. XX, No. 5, p. 34, 1894. Porat here proposes to refer even such 
species as Rhododesmus mastophorus (Gerst.) to Paradesmus, with the result 
of bringing members of at least three families into an invalid genus, the type 
of which belongs to a fourth family, and the name of which is preoccupied. 
Branutia, p. 15. 
