244 A 3Ionograjyh of Scytonotus. 



3. The ventral face of the third joint is more or less papillose 

 on legs S-^r, 9-12, and 18-29. The papilhe are few on legs 3-12, 

 and are confined to the distal part of the joint. On the 18th legs 

 there is a papillose area near the middle of the joint, while on the 

 19th and 20th the roughened surface is large and prominent, 

 with more scattered papillre covering a large part of the A'entral 

 face of the joint. On legs 21-29 the papilhe are about the same 

 as on 3-12, becoming gradually fewer and smaller. The absence 

 of papillfB on legs 13-17 is noteworthy, considering the fact that 

 these legs are much modified in other respects. 



4. The third joint of legs 19 and 20 is stouter than that of the 

 others and has its distal margin noticeably more oblique, condi- 

 tions probably correlated with special roughness of the joints of 

 these legs. 



5. The fourth joint is papillose on its inner face on all the legs 

 except numbers 1 and 13-17, which have the third joint also 

 smooth. 



6. The fourth joint of legs 19 and 20 is shorter, broader, and 

 more papillose than the others. 



7. On legs 13-18 and 21-23 the apical margin of the fourth 

 joint is ver}" oblique, probably to make it possible to flex the 

 enlarged fifth joint. Thus the oblique margin of the fourth ]o\\it 

 of these legs corresponds functionally to that of the third joint 

 of legs 19 and 20, or in other words, the fourth joint of legs 19 

 and 20 has become a part of the fifth, while that of legs 13-18 and 

 21-23 is functionally more like a part of the third. The peculiar 

 form and the abundance of papilhe on the fourth joint of legs 19 

 and 20 give force to this suggestion. Transitions between the 

 two types of arrangement are not wanting, for legs 18 and 21-23 

 gradually shade off into the normal form. When, however, we 

 compare 13 Avith 20 there can be no doubt that the necessity of 

 special provision for flexing the abnormally crassate joints has 

 been met in two different ways. 



8. The ventral face of the fifth joint of all the legs is papillose, 

 except that the roughening is nearly or quite obsolete on the first 

 pair. On legs 13-20 the roughened surface is much more 

 extensive. 



9. Legs 13-20 have the ventral face of the fifth joint much in- 

 flated, most on the 13th, and slightly less on the 14th, 19th and 

 20th. The prominent papillose surface is much longer on the 



