16 



PEOCEEDIN"GS OF THE NATIONAL MUSEUM 



VOL. 78 



of the left posterior appendage by the side of the right, (pi. 1> 

 fig. 2 and fig. 4:d.) 



(c) Lenfj^th about 50 mm., verj^ imperfect and curled up, 8 ap- 

 pendages clearly defined. 



(d) Length about 12 mm., a small curled specimen poorly pre- 

 served with at least 9 appendages. 



(e) Posterior fragment, 24 mm., 8 appendages. (PL 1, fig. 1.) 

 (/) Length 28 mm., 10 or 11 appendages. 



{g) Length about 25 mm., curled; at least 9 apiDendages. 



(A) Length 14.5 mm., 11 appendages. 



jSise and number of segments. — From the above list it is clear that 

 Aysheaia reached a size of about 50 mm., that the best preserved 

 specimens show 11 segments bearing conspicuous appendages, and 

 that this number is the same in both small (14.5 mm.) and large 

 (45 mm.) animals. The detailed structure of the animal is best 

 indicated in the two specimens designated as {a) and (6), the latter 

 being illustrated in Plate 1, Figure 2. 



Body wall. — The dorsal edge of (&) shows a row of papillae 

 compressed sideways, representing the most dorsal papillae of a 



• i I S S t i 





Figure 5. — Atsheaia pedunculata Walcott, conjectural eestokation 



series of transverse rows which can be made out in all the speci- 

 mens. Except on the dorsal margin of (h) the papillae are chiefly 

 represented by small apical pits wdiich probablj^ each bore a minute 

 seta as in modern Onychophora. At least 4 papillae are found dor- 

 sal to the gut on the riglit side of (5), so that the upper half of each 

 ring had at least 8. Walcott made out 13 in a row on the type, 

 probably the complete annulus consisted of 14 or more. Four an- 

 nuli appear to correspond to each appendage in the trunk region, 

 and so to each segment; there are, moreover, 4 annuli of papillae on 

 the anterior end of (&), which clearly correspond to the segment 

 of the branched appendage. 



Legs. — The legs appear in all the specimens as the flattened re- 

 mains of slightly tapering truncate cylinders. They are annulated, 

 as are those of recent Onychophora, the best preserved show at least 

 8 annulations. Each leg ended in a group of claws; on the fourth 

 right leg of (a) 6 claws can be distinguished, 3 turned forward and 

 3 backward. (Fig. 45.) On the other legs onl}?^ 3, 4, or 5 claws can 

 be found. In (6) the claws are all turned backwards; it is probable 



