ELISHA MITCHELL SCIENTIFIC SOCIETY. 45 



are crowded. Eyes can be better described by speaking of them as X>e- 

 ing in three groups ; the anti-centrals a diameter or less distant and sit- 

 uated at the top and on sides of the hill ; on each side of these, not far 

 separated is a group of three eyes forming a crescent with the concavity 

 toward the midd e group; the eyes in this group nearly or quite touch 

 each other. Fig 8, PI. V, represents the eyes as seen from the Iront at an 

 angle of 45^ to a plane parallel with the base of the ceph'x 



With this view the ant- and pott-laterals form a trapezium, base at 

 post laterals one-fourth larger than opposite side; height about one- 

 third of base, post centrals slightly in front of base of trapezium. Ant- 

 laterals comparativtly large; others varying in relative size in different 

 fcpecies, and it may be found that the relative position varies also as in 

 Pachylomerus. Maxillae extended in front, but not so much as in Eriodon. 

 Fig. 10 represents a maxilla showing insertion of palpus. Labium 

 triangular, distal end rounded, longer than broad at iDase. Mandibles 

 strongly kneed in front of pprpendicular clypeus. 



About half or less than half as long as ceph'x , br )ad and deep, armed 

 with a compar.itively strong fang ; the inner edge only of furrow for re- 

 ception of fang arme I with terth ; upper and inner edges of anterior half 

 armed with short spines, which also extend part way around base of 

 fang. 



Legs 4, 1, 3, 2. 4, 1, 3. 3, or 4, 1, 2, 3 ; palpi long. 3 tarsal claws. 

 Claw of palpus unarmed. Abdomen short oval. Spinnerets 4, the upper 

 pair long and slender. 



1. Nidivalvata marxii, n. sp.' female 1 specimen. 



(PI, V, figs, 8, 9, 10, 13, 23.) 



Ceph'x broadly oval 6 mm long by 5 mm. broad Caput back of 

 ocular prominence not perceptibly elevated, slope down to depression in 

 center of ceph'x gradual. Caput in front not much contracted on sides. 



Radial depressions all quite deep ; the posterior one of the laterals on 

 each side, seeming to unite with the central depression. The depressions, 

 though distinct in this specimen, have d<-epened somewhat by alternately 

 being in alcohol and in the air while being studied. 



In each anterior radial depression on sides of base of caput is a well 

 marked depres-ion, though not deep 



Post-central eyes fully as large as the ant centrals, eyes of the outer 

 group almost or quite touching. Ant-laterals dark orange, remainder 

 transparent, legs 4, 1. 3, 2. 3rd 12 mm., 2d Hi mm. Sternum longer 

 than broad, with three distinct circular punctures on each side. Abdomen 

 ])roadly oval and bluntly rounded at eacti end ; on ventral surface nar- 

 rowed in front 



Armature Very few hairs ; short and fine on abdomen, longer and 

 darker on the 4 distal joints of legs. Metatarsus IV, w.th a row 01 spines 

 on each side, and one on under side, with additional spines at each end; 

 tibia IV, witli few long spines irregularly placed on upper side, 3 dis- 

 tinct rows, two on under side and one on anterior side, with extra spines 

 at each end. Patella two double rows ot spines on upper surface. 

 Metatarsus III, 4 rows of spines, two upper and two lower edge: spines 

 irregularly placed on upper side. Patella III, patch of spines on upper 

 anterior surface, broadesr, at distal end; this is separated from a few 

 spines on the p)steri()r surface by an oblique denuded line. Metatarsus 

 II, two double rows of spines, one on anterior surface, and one of long 

 spines on under surface; tibia II and I, double row of long spines on 

 under surface, and single row of short spines on anterior surface. Met- 



^ In honor of Dr. Geo. Marx. 



