studies iiti in, mill' Ostracods 13 



— the small size of the figure, the method of reproduction, etc. — 3) it seemed exceedingly 

 important to give a verification of the figures by means of the text. 



With regard to the description of the shell we must note: 

 All shell measurements are taken by means of an ocular micrometer. Like most preceding 

 authors I have, when measuring the length of the shell, included any processes that were 

 present, e. g. the rostrum, spines, etc. In his measurements of H a 1 o c y p r i d s and C y p r i- 

 dinids G. H. FOWLEH, 1909, measured ,, parallel to the dorsal border from the most pro- 

 ininent part of the anterior border, ventral to the niche for the second antenna" to the most 

 projecting part of the posterior border, leaving out of account any spines that might exist. 

 This method of measuring was to give ,,a real measurement of the shell, which is comparable 

 in different species" (loc. cit. p. 222). As I never had any need of any such „real" values, 

 I have, as stated above, employed the method used by other investigators. 



G. W. MlJLLER writes, 1894, p. 9, as follows: ,,Die meisten Untersuchungen an der Schale 

 konnen mit Erfolg nur an isolierten Schalen vorgenommen werden, besonders soUten Profil- 

 zeichnungen nur nach ihnen gemacht werden . . . ." This principle has been applied to as 

 great an extent as possible in the present work. Only in cases where it was impossible, on 

 account of the soft condition of the shell, to separate the two valves without destroying the 

 form has the profile been drawn from the whole shell. In the latter case the body was almost 

 always first removed from the shell. ,,Man ist dann leichter im Stande, das Thier in (.lie 

 Profillage zu bringen" (G. W. MOller, 1894, p. 10). 



During the drawing of the profile the shell is most conveniently fixed, if it is drawn 

 whole, by means of gelatinous glycerine. 



G. W. MOller writes as follows in his work of 1894, p. 9, with regard to the shell: ,,Maii 

 untersuche, wenn auch vorwiegend, so doch nicht ausschlieBlich in Canadabalsam oder Nelkenol. 

 sondern auch in Glycerin, eventuell auch in Wasser oder Alkohol, da liautig Einzelheiten der 

 Sculptur in Canadabalsam vollstandig verloren gehen." To this it may be objected that it is 

 absolutely necessary to investigate and reproduce sculptured shells in a dry condition and 

 in reflected light. If the shell is investigated in a liquid we may easily obtain a mistaken 

 idea of the sculpture whether we use reflected or transmitted light. — The reproduction of the 

 sculpture as it appears in transmitted light is of course inconvenient, because by this the identi- 

 fication of fossil forms is rendered much moje difficult. 



The figures of the shells ought to be made comparatively large and as similar in details 

 as possible; generalized and minute figures, such as those of G. S, Brady, are of little use to 

 us; sculptured shells ought to be reproduced by means of shaded figures, not figures of the 

 type given by G. W. MUller in his work of 1908; unsculptured shells are drawn most con- 

 veniently in transmitted light and without any shading. 



The cross-striatioii of the selvage is most often very slight; it is exaggerated in the 

 drawings in order to show what is selvage. 



In describing the 1 i m b s we m u st n o t e: Tiie relative lengtli of the joints 

 of an appendage has sometimes been shown below in a way that is illustrated by the foUowing 

 example: I ^; II ^: III y . . . . N'lll 0.5. Here the nirnaii figures denote the numbers of tlir 



