70 



lowest and that in recent Ostracoda tlje lowest end is generally 

 anterior. Another reason for his lino of conduct was the conjecture 

 that the large node into which the lower of the two nodes has 

 sometimes passed at one end, must be considered as the lodging 

 place of the genital apparatus of the female individuals, whereas 

 Zenker had said that in recent Ostracoda this genital apparatus fills 

 the widened and heightened posterior part of the shell. 



This conception of Reuter was again refuted by Jones (16, p. 339) 

 and KiESOW (17, p. 2) but like Reuter, they failed in furnishing 

 convincing evidence. 



Therefore Krause (18, p. 12 ; 19, p. 4) proposed to retain the 

 position most assumed till it should be proved wrong. 



At a later date Ui-rich (20, p. 630) was also of opinion that for 

 the time being the best plan would be to follow the rule indicated 

 by Jones and regard the least developed end as anterior. 



In 1908 Ui-RiCH and Bassler (21, p. 280) in a paper on the 

 Beyr'ichiiilae devoted a chapter to this question and tried to solve 

 it by the following way of reasoning. 



With the species of the genus Leperditia the shells have on both 

 valves near one end a so-called eye-tubercle, which as is universally 

 accepted b}^ paleontologists is to be connected with the visual 

 organs. Therefore in Leperditia shells the end with the eye-tubercles 

 is the anterior end. As the shells are lowest in front here and most 

 developed behind, owing to a strong retral swing of the posterior 

 edge, they assume that this is also the case with the Beyrichiidae. 

 They apply these rules also to Beyvicliia tuherculata and find then 

 that the position suggested by Reuter, is the right one. 



Soon after the publication of Ulrich and Bassler's paper I found 

 an opportunity of indicating that the rules given by these writers, 

 as far as the Ostracoda of the Kuckers formation are concerned, 

 were altogether at variance with the results I had found. 



Moberg and Grönwall (23, p. 55), who the year after gave a 

 terminology for the Beyrichian valves, accepted the position such 

 as it had been suggested by Jonp^, but added : 



"Dock bör framhallas, att denna terminologi pa paleontologiens 

 nuvarande standpunkt ar endast hypotetisk, afven om mycket talar 

 till gunst for densamma." 



And this is the present state of the question. 



As I have said already, 1 think I have enough data now to solve 

 the problem and from this it will appear that the position suggested 

 by Jones, is the right one. In doing so I must make use of what 



