No.im. THE FAMILY GOMPHODESMJDAi— COOK. 713 



less densely liiraute; ventral faeo of four distal joints M-itli niinnte 

 tubercles; llesliy soles of lastjoint of pairs 1 to inoderately develojx'd. 



Copulatory legs (Plate LVII, figs. 4a-4c'). 



Color of alcoholic specimen i)ale grayisli brown, the carina', I(!gs. and 

 antenna- sordid; the wiioh? animal l)lea(',hed in alcohol so that tlie darker 

 contents of the alimentary canal show thronjiii. Karscii gave the color 

 as uniform pale testacteous in 1.S.S1. 



Length, about 40 mm,; widtii, 7.2 mm.; length of antenna, 7 mm.; 

 of leg of tenth segment, 7.5 mm. 



LocaUty. — Seril)a (Jhattas, DJur, in tiie n])[)er valley of the White 

 Nile (Bahr-el-Ghazal region); a single male specimen ])re8erved in alco- 

 hol in the lierlin IMuscsum Avas (jollected by l)i-. S(;hweinfurth. The 

 bottle (No. (>21)) contains also a fragment consisting of segments 12 to 20 

 of what was evidently another s))eciinen of the same si)ecie8. 



This species was referred i)rovisionally to the genus Ti/codcfiiiins on 

 a(;count of its size and habit, the chai'a(;ters from wiiich the genus 

 might be more accurately determined not being given in the original 

 descri])tion. 



'J\i/mho(h'8mu8 falcatus differs i'roin T.Jif/Unun in the following impor- 

 tant characters which may indicate generic distinctness, although the 

 form of the copulatory legs is good evid(mce that the two are more 

 nearly related to each other than to any known third. T. J'alcaiuH 

 is less than half as large as T. fiyiinun, the segments, legs, and 

 antenme are more slender and delicate, the dorsum is less convex, 

 the lateral thickenings of the carinas are le.ss ))romin(;nt dorsally, but 

 are turned sidewise more than in any other form here descril)e<l, so that 

 the i)oriferou8 dei)ressions lace nearly laterad and cause the (uirime to 

 appear emarginate when viewed from above; the processes of the sterna 

 of the sixth and fifteenth segments are small, nariow, and not medianly 

 snlcate. They are both rounded triangular in outline, that of the si;cth 

 segment having no lateral lobes or shoulders, which are strongly devel- 

 0])ed in 7'. fifilimis. The sterna of segments 8-10 have the ])osterior pair 

 of ridges increased into flattened knobs, while h\ fujlinuH ev(Mi the i)ro- 

 duced pair of the eighth segment are thin and shar)) at apex. The 

 copulatory legs in falcatus have the node vei-y prominent laterad and 

 l)ro])ortionally much larger than in Jiylinus and occupying the entire 

 sinus of the curve; in T.JifjIinm the upper part of the sinus is open, 

 the node is strongly constricted at base and bears sharp teeth on its 

 median and lateral faces, the homologous jirominences of T. JalmtuH 

 being, as far as they can be distinguished at all, mere rudiments in 

 comparison. 



Genus AULODESMUS Cook, 



Aulodesmns Cook, Proc. U. K. Nat, Miik., 189."*, XVIII, p. Hli. 



Body very large, live times as long as broad, tapering slightly candad; 

 dorsum strongly convex, the carina- decurved in the direction of the 

 dorsal arch. Antenna' filiform, second Joint longest, the next four 



