450 SAMUEL H. SCUDDER ON THE 



eeplialothorax shows a shallow, profuse, moderately coarse punctuation; the abdomen a 

 transverse, fine, but irregular corrugation in which the furrows seem occasionally to be 

 deepened by punctures. 



Length, 14.75 mm. (eeplialothorax, 5 mm.; abdomen, 9.75 mm.); breadth, 5.25 mm. 



Braidwood, III., from the same horizon as the Mazon Creek beds at Morris. Mr. R. 

 D. Lacoe, No. 1702ab.- 



KuSTARACHNE (Kusta, nom. propr., "pa/^v) gen. nov. 



Proposed for a genus of carboniferous arachnids presumed to belong to the Anthra- 

 comarti and the family Architarboidae. The eeplialothorax is orbicular, more or less 

 embracing at its base the regularly ovate abdomen, l)ut not so as to prevent a decided 

 constriction between the two laterally. In the single specimen yet known, the elements 

 are too uncertain to distinguish it in this j^art from the other genera. The legs which 

 seem to have a stout basis are long and exceedingly slender. The palpi have the same 

 slenderness but only the base is preserved. The abdomen proper is considerably larger 

 than the cephalothorax, divided into seven segments, of which the first four are equal 

 and longer than the last three, which are followed by a protuberant 2)ygidium composed 

 of two subsegments. It is possible that this was followed by a jointed seta; if so it could 

 hardly fall in this place, but among the Pedipalpi Avhere it would differ strikingly from 

 the known foi-ms. The irregular divisions of the abdomen do not disturb the I'Cgular 

 curve of the sides. 



Named in honor of Professor Johann Kusta of Eakoiiitz who has so greatly enlarged 

 our knowledge of carboniferous Arachnida by his stutly of the coal-fauna of Bohemia. 



Kustarachne tenuipes sp. nov. 

 PI. 40, fig. 7. 



The exact limits of the cephalothorax in the only specimen are rather obscure but so 

 far as can be seen this region is orbicular with a slightly greater breadth posteriorly. 

 The radiation of the coxae from the central pit is a little obscure, but unquestionable, 

 and the pit opens posteriorly with flaring sides. The legs are excessively slender, long, 

 straight, and almost thread-like, and the palpi have at base the same form, two short and 

 slender joints of one being visible. The abdomen is very regularly oval, the broader 

 basal extremity being sessile but having its basal suture well defined and the latei'al ex- 

 cision at their boundaries distinct; the last three segments of the abdomen jiroper, which 

 are equal, are about half as long as the four equal, basal segments; the terminal subseg- 

 ments interfere with the regularity of the foi-m of the abdomen, extending beyond the 

 oval; the first is of the same length as the terminal segment, but only half its breadth 

 and semilunar in form; at either side of its base a possible globular appendage appears to 

 be present; the last segment is as long as the penultimate but much slenderer, being fully 

 half as long again as broad; and there arc some indications on the stone (which may be 

 fortuitous) that it was followed by a slender seta; the surface of the abdomen is faintly 

 and shallowly punctate. A straight belt of lighter color than the sides and as wide as the 



