C. L. Edwards 
267 
assumed that this, like Type A, is characteristic of the pedicel. Sometimes 
perhaps the presence of Type B may indicate that the pedicel is not fully 
developed. 
Type C, only found in 9 of the dorsal appendages, has a frequency of 
2 (25 7o) ill cylindrical, 2 (37'5 "Z^) in conical forms, and 3 (37'5°/^) not determi- 
nable. This type may be taken as an intermediate stage. 
Type D occurs but once and then the form of its appendage is not deter- 
minable. 
f. A.SSOCIATION OF SuCKERS WITH TyPES OF EnD-PLATES. 
Of the appendages with Type A end-plates 39 (95"1 °/^) have suckers and 
2 (4'9 7o) ^re not determinable and with Type B 32 (88-9 °/^) have suckers, 
1 (4'9 7o) has a rudimentary sucker, and 3 (8"3 are not determinable. As none 
have them absent in these two classes and only 1 with Type B is rudimentary it 
may be assumed as the rule that Types A and B of end-plates are found in appen- 
dages having suckers. 
With Type C the suckers are present in 2 (25 rudimentary in 1 (12'5 
absent in 3 (37*5 °/J and not determinable in 2 (25 °/J of the appendages. The 
one case with Type D is uncertain but probably has a rudimentary sucker. 
g. Association of Supporting Rods with Types of End-plates. 
Of the dorsal appendages with Type A end-plates, supporting rods are present 
in 16 (39 7J, absent in 17 (41-5 7J and not determinable in 8 (19-5 7/); with 
Type B they are present in 4 (111 °/^), absent in 17 (47"2 %) and not determinable 
in 15 (41-7 7o); ■^vith Type C they are present in 5 (G2'5 "jj, absent in 1 (12*5 °/J 
and not determinable in 2 (25 °/J ; and in the only one with Type D, the rods are 
present. 
h. Conclusions and Definitions. 
In the evolution by degeneration of the papilla from the pedicels the form has 
become conical with more and more pointed tip, the sucker rudimentary and 
finally lost, the end-plates smaller to vestigeal rosettes and supporting rods more 
frequent. The smaller diameter of the end-plates in the bivium, with the addition 
there of Type D, and more of Type G, indicates the greater progress of this evolu- 
tion in the dorsal region. 
The typical pedicel is cylindrical in form, with functional sucker, having end- 
plates of Type A in a, large majority of the cases, the rest being of Type B, and 
dorsally with supporting rods more often absent than present. 
The typical papilla is conical in form, without sucker, having end-plates of 
Type D, or E, and with supporting rods present. 
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