416 The American Natu 



En- 



large number of forms the poriferous segments are wholly or partly red 

 or yellow, while the remainder of the body is nearly black, giving a 

 most striking appearance. Prepodesmus includes several such forms, 

 all with the anterior corner of the second segment greatly produced and 

 embracing the first segment. Tylodesmus has the corner rounded and 

 not produced. Cheirodesmus is similar to the last in general shape, 

 but is more slender and with the male genitalia resembling in shape a 

 gloved hand. Anisodesmus is peculiar in that the fourth segment is 

 distinctly, though slightly, narrower than the third or fifth. The 

 species are uniform dark red in color and the type is closely allied to 

 Polydesmus erythropus Lucas. Isodesmus is evidently related, but with 

 the fourth segment not narrowed, and remarkable in that the pores are 

 not borne on a distinct callus as in the other genera of the group. The 

 copulatory legs are also very peculiar being deeply divided into 

 several laciniae. In all these genera the dorsal surface is finely and 

 evenly granular, though differing somewhat in other respects. The 

 family is probably distributed along the entire West Coast, and I have 

 seen two forms from South Africa, one of which, Lipodesmus, is in the 

 Berlin Museum. 



Family Oxydesmid;e. 

 The Liberian forms which belong to this family in the more limited 

 sense 3 are all referable to the genus Oxydesmus, and belong to three 

 species, 0. grayii Newport, 0. medius and 0. liber, both new. The first 

 is a very striking form, black in color with a narrow median stripe of 

 bright vermillion. The other species are also black, 0. liber with 

 bright yellow submarginal ridges. 



Family Polydesmidje. 

 Of Liberian species referable to this family in its stricter sense there 

 seem to be but two; small pinkish-red forms, similar in general appear- 

 ance to some species of Brachydesmus. The dorsal elevated areas are 

 each supplied with a clavate hair. The antenna? are strongly clavate, 

 though rather slender, and the second pair of legs is crassate in the 

 3 The African forms having the apex of the last segment broad, the femora 

 spined, and the carina* with a submarginal ridge, constitute the family Oxydesm- 

 idse. There are five genera now known, two confined to the east side of the con- 

 tinent, three to the west. Of the east coast forms, Orodesmus includes those with 

 strongly tuberculate segments, Mimodesmus those with the body slender and the 



dorsal tubercles and surrounding areas ; Scytodesmus has five or six rows, while 

 Plagiodesmus resembles Oxydesmus, but has the submarginal ridges very' broad 

 and oblique, and the copulatory legs large and exposed. 



