no. 1831. XF1)V TROPICAL MILLIPEDB—COOK. 461 



Cariuse divided by deep incisions into numerous lobes; lateral margin with two 



lobes. Genus Iomus, type i". incisus Cook, from Porto Rico. 

 Carinse with dorsal areas separated only by shallow grooves and notches. 



Dorsum strongly and evenly convex, with three transverse rows of convex 

 smooth rounded or polygonal areas; lateral carinae narrow, depressed, the 

 pores large and distinct. Genus Chytodesmus, type C. laqueatus (Karsch), 

 from Cuba. 



Dorsum slightly convex, with indistinct transverse or radiating, roughened or 

 hispid areas; lateral carinas broad, nearly horizontal; pores very small. 



Poriferous carinas with four marginal areas or lobes, the others with three; pos- 

 terior area not strongly enlarged; last segment rather long, truncate at apex, 

 with a distinct rounded lobe on each side. Genus Docodesmus, type D. 

 vincentii (Pocock), from St. Vincent. 



All the carinae with three marginal areas except at posterior end of body; pos- 

 terior area much enlarged and somewhat produced on poriferous segments; 

 last segment very small, triangular rounded at apex, entire. Genus Tri- 

 desmus, type T. sectilis Cook, from Porto Rico. 



NOTE ON SOUTH AMERICAN CHYTODESMID.E. 



Another member of the Chytodesmidse was recognized several 

 years ago in the Berlin Museum among the spec- 

 imens from Bogota, Colombia, included by Peters 

 in his composite species Cryptodesmus alatus. The 

 repugnatorial pores open on a special tubercle 

 near the posterior corner of the carinse, as in the 

 West Indian genera Docodesmus and Tridesmus. 

 It differs from these West Indian relatives in the 

 very small size of the body and the very slight 

 and poorly defined dorsal sculpture, consisting 

 of a few large rectangular or polygonal areas, fig. 5.-stictodesmu3 

 The following characters are described from notes creper. segments 1-6. 



. „ ,° -p. ,. Dorsal view 



and figures drawn at Berlin: 



STICTODESMUS CREPER Cook. 

 Stictodesmus creper Cook, Brandtia, p. 20, June, 1896. 



Body composed of 19 segments, length 4.2 mm., width about 0.8 

 mm., being the smallest of the specimens originally assigned by Peters 

 to his Cryptodesmus alatus. 



First segment much narrower than the second, not completely con- 

 cealing the head and the distinctly clavate antennae; shape of seg- 

 ment subelliptic, or broadly fusiform, much more nearly symmetrical 

 than usual; a line connecting the lateral angles would nearly bisect 

 the segment. (See fig. 5.) 



Segments with two rows of somewhat distinct dorsal areas on each 

 side of the impressed median line; other areas not distinct. 



Lateral carinas less than half as wide as the body-cylinder, deeply 

 grooved and notched in the middle of the otherwise entire posterior 



