Furtlier Observatious ou Koeuenia. 415 



larger tlian aiiy spine of K. mirabüis and is by far tlie largest 

 seta found oii Koenenia uiieeJeri. This too is foiind on the youngest 

 stage of our species, though it may be easily overlooked from the 

 fact that its flat surface is often applied close to the appendage. 



3. The Position of two groups of setae, which are arranged in a line 

 diagonally across the ventral surface of the proximal Joint of the 

 chelicerae, is another characteristic of Koenenia wheeJeri which occurs 

 in the earliest known stage. The first and most anteriorly arranged 

 of the two groups consists of three rather stiff, blunt setae which 

 are delicately plumiüose and project across and under the mouth. 

 The second group consists of two larger and one very small and 

 more pointed setae which possess for almost their entire length on 

 their inner side a line of secondary hairs. These setae likewise 

 project forward and diagonally under the mouth. 



4. The terminal joints of the chelicerae represent a condition 

 which to judge from the description given by Dr. Hansen of other 

 species, must be entirely characteristic of the Texan form. This is 

 the arrangement of the teetli on both the movable and flxed joint.^) 

 After examining the largest specimens to be had in glycerine, in 

 KOH, and tlien stained and mounted in baisam. I feel satisfied that 

 the true state of affairs is revealed in the results given below. 

 Looking down on the chelicerae from above, when they are stretched 

 out, one sees a small row of denticles which begins near the 

 level of the second tooth from the distal end aud runs parallel with 

 the eight large teeth, and merges into that row at its proximal 



I termination, wliere on the fixed Joint, the two ridges dwindle into a 

 'Serratien, that is continued further into the end near the spot where 

 a seta is given off. On the movable Joint this Serratien is absent 

 and the two rows end with an obtuse angular projection. These 

 ' denticles are not projections of the teeth but arise from a distinct 

 1 ridge, which lies close against the base of the teeth. The alternating 

 arrangement of the teeth and the denticles is quite evident and it 

 is this that gives the zigzag appearance to the teeth when looking 

 straight down on them. 



5. In those specimens which I have examined for this purpose 

 I have always found six hairs on either side of the labrum arising 

 from the edge, projecting over the mouth and overlapping the 



^) In my previous paper I had thought that the row of denticles on 

 he movable Joint were not denticles but the reflection of light from the 

 lollowed bases of the large teeth. 



Zool. Jahrb. Bd. XVIII. Abth. f. Syst. 28 



I 



