It. I. PococJc — On Eophrymis and Allied Arachnida. 445 



second tergal plate, perhaps partially or completely fused with the 

 third. If this be so, there will be nine tergal sclerites visible on 

 the upper side of the opisthosoma, at all events in this species of 

 Anihracomartus. 



Haase's ^ figure of the segmentation of the dorsal side of the 

 opisthosoma of A. volTcelianus is open to the same interpretation. 

 A distinct, though short and narrow plate is represented between 

 the posterior border of the prosoma and the lightly emarginate 

 anterior border of what he regarded as the first tergite of the 

 opisthosoma. If this hitherto disregarded sclerite be counted as 

 the first, the opisthosoma of the specimen in question presents nine 

 visible terga when regarded from above. This view of the matter 

 reconciles certain differences in the structure of the anterior segments 

 of the opisthosoma in A. volkelianiis and A. palatinus, which the 

 older hypothesis left unexplained. 



In the case of Kreischeria, again, Haase and Geinitz depict and 

 describe eight terga, and there are only eight rows of tubercles. 

 But between the posterior border of the carapace and what is 

 regarded as the first tergum a narrow sinuous area is figured which 

 may be the tergum of the first genuine somite. Its size and lateral 

 attenuation certainly suggest the first tergite of Anthracomartus 

 palatinus ; and it further resembles the first plate in Eophrynus 

 prestvicii in being embraced at the sides by the lateral laminee of the 

 second, which are directed obliquely forwards and outwards. If this 

 theory be adopted the differences between the first and second terga 

 in Kreischeria and Eophrynus prestvicii are very considerable, for in 

 the latter it is the second that is in process of obliteration and has 

 become modified by the suppression of its tubercles, the first 

 remaining normal in these particulars, while in Kreischeria the 

 converse holds. 



Another view of Kreischeria, however, may be entertained. The 

 tergum that Haase regards as the second is much larger than those 

 which he counted as the first and third, and it is possible that it 

 represents two terga, namely, the second and third entirely fused, the 

 process of fusion that is indicated in E. prestvicii having been carried 

 to its completion in Kreischeria. This supposition gains some 

 support from what is presented in the allied Arachnid Brachypyge 

 carbonis, where the second tergal plate is also of large size and 

 may represent the dorsal elements of the second and third, there 

 being only eight terga traceable on the upper side of the fossil. 

 There are reasons, too, for thinking that the first tergite also, 

 although clearly enough defined, is fused to the second large 

 plate in the form just mentioned. 



These doubtful points will no doubt be settled by a re-examination 

 of the fossils in question. In any case there appears to me to be 

 no escape from the conclusion that nine tergal plates are visible 

 on the upper side of the opisthosoma in Eophrynus prestvicii. As 

 is explained below, the first of these has apparently no sternal 



1 Zeitschr. deutsch. geol. Ges., vol. xlii.(L890). 



