565.3309 i8i 



IV. 



The Literature of Fossil Ostracocls. 



THE common Cypvis of our rivers, ponds and ditches, or the various 

 genera, both freshwater and marine, belonging to the same class 

 of animals, have had representatives or close allies in every geological 

 period from the Cambrian downwards. It is the purpose of this 

 sketch to bring before the readers of Natural Science a general idea 

 of the amount of work already done on this group, and the probably 

 great amount of ostracod material preserved in the rocks beneath us. 



Up to the year 1855, valves of Ostracoda from Palaeozoic rocks 

 had been described here and there, with other fossils, but little serious 

 attempt had been made to study any of the groups as a whole, or to 

 classify such forms as had received the scanty technical attention 

 given by the collectors of these fossils. In 1855 Professor Rupert Jones, 

 then assistant secretary of the Geological Society, commenced a series 

 of papers on the subject in the Annals and Magazine of Natural History, 

 a series which has now reached number xxxii., and has provided 

 material wherewith to study and classify the whole known group. In 

 the elucidation of the various forms as they came to hand, Professor 

 Jones had, from time to time, the invaluable assistance of Harvey B. 

 HoU and James W. Kirkby, and these authors between them have 

 published a vast amount of information on a most difficult group. 



The Palaeozoic Ostracoda present so many anomalies, that 

 comparison with recent forms is often impossible, and deductions that 

 were at first drawn have had to be abandoned as fresh material has 

 come to hand. The singular protuberances found in the carapaces of 

 the genus Beyvichia, with their hundred and one modifications, and 

 the still more remarkable projecting spines of ^chmina, seem to baffle 

 suggestion as to their use and meaning. 



An illustrated account of some of these early forms appeared in 

 1869 in a paper, now very scarce, published by the Geologists' 

 Association of London. This gives the student a very good idea 

 of the various modifications undergone by the ostracodal carapace. 

 In 1886 [Quart. Journ. Geol. Soc.) Jones and Kirkby gave a synopsis 

 of all British " Carboniferous " forms, arranged to show their zonal 

 and geographical distribution, and further showed that while the 

 genera provided a more or less safe guide to stratigraphy, the species 



