DESCRIPTION OF PLATES. 191 
of the parent-form, but necessarily on a larger 
scale, as 1t contains the material which before 
made up two individuals. These larger diatoms, 
resulting from conjugation, multiply again by bi- 
nary division, and in the course of a number of 
generations the size is diminished to that of the 
individual members of the conjugating pair. It 
will be seen that in these marriages in low life, 
the twain literally become one flesh. 
List or Diatoms In Puate XII. 
Abbreviations used: F. W., fresh water; M., marine; B. W., brackish wa- 
ter; V., valve; U. V., upper valve; L. V., lower valve; P. V., principal view. 
First Line. 
No. 1. Isthmia enervis. M. North Sea. 
2. ‘¢ nervosa. M. California. 
«6 3. +Biddulphia pulchella. V.,M. Zongatuba. 
ce 4, ce 79 Pp. V. 66 
o. By &¢ Roperiana. V., M. Australia. 
ee 6 - oe oe Pp, Vv. ce 
ee ce Aurita. Peru- Guano. 
“8. ce reticulata. M. Australia. 
a ee Baileyii. M. Cuxhaven. 
se 10. ee Rhombus. M. Cuxhaven. 
“11. Cerataulus turgidus. M. Australia. 
ce 12. #6 Smithii. M. Cuxhaven. 
Second Line. 
No. 1. Euodia gibba. Fossil. Spain. 
tes ‘¢ Frauenfeldii. M Australia. 
‘© 3. Corinna elegans. V. Fossil. Jutland. 
oe 4, (79 ce P. Vv. 
“=. ~=6Triceratium favus. M. Flolstein. 
cc 6 ee fimbriatum. M. Australia. 
