418 



ANIMAL NATURE OF DIATOME^E. 



equal to two millimetres. This line is one peculiar to 

 himself; for the line of English measure, which is the 

 smallest of all, exceeds two millimetres in measurement. 

 Kutzing makes use of a linear measure with the same 

 notation as that used by Ehrenberg, three small marks, 

 which usually indicate the millimetre, to the right of the 

 cipher. It would appear that he intends to speak of 

 the same conventional line; at least I arrive at this 

 conclusion from the following comparative table of the 

 extreme length of some species of Navicula, deduced 

 from direct observation, from the cipher of Ehrenberg 

 and that of Kiitzing, on the double supposition of the 

 line being conventionally equivalent to two millimetres, 

 and to the line of the Parisian inch = 2'707 centim., and 

 from Kiitzing' s figures.* 



Navicula ampbisl&na . . . 



Ehrenberg, 5 y" . . . 



Kiitzing, &'" 



Kiitzing's figure, 0*021 (^) . 

 Navicula cuspidata . . . 



Ehrenberg,*'" . . . 



Kiitzing, 5 ' 3 "' .... 



Kiitzing's figure, 0-0242 (if) 

 Navicula appendiculata . . 



Kiitzing, s ' ? .... 



Kiitzing's figure, 0-0093 15 (||S) 

 Navicula viridula . . . 



Kiitzing, " . . 



Kiitzing's figure, 0-0192 

 Navicula gracilis ... 



Kiitzing, 5 V" 



Kiitzing's figure, 0-0207 

 Navicula major . . . 



Ehrenberg, i"' . 



Kiitzing, $"' . . 



Kiitzing's figure, 0'058 ( 

 Navicula oblong a . . 



Ehrenberg, T V" . 



Kutzing, T V" . . 



Kiitzing's figure, 0'0466 



0'070 millim. 



0100 



0-0760-104 



0'050 



0'070 



0-133 



0-0870-117 



0-0576 



0'027 



0-0370-050 



0'022 



0'047 



0'062 0'084 



0'0457 



0'054 



0-076 0-104- 



0-049 



0-235 



0'333 



0-2220-300 



0130 



0135 



0-166 



0-1800-246 



0110 



It results from this table that the ciphers of Kutzing 

 express, in fractions of a line (equal two millimetres), 



* In the present translation the decimal numbers indicate millimeters or 

 parts when not otherwise marked, and parts of a line are given in common 

 fractions with the sign "'. ED. 



