86 HISTORY OF THE OCEANS 



suitable questions. My hope is to show that with a Httle patience 

 and insight this is not really the case. 



In order to investigate the matter it is, as I have just indicated, 

 necessary to have patience, for we shall first have to examine 

 rather closely the problems of the classification and so implicitly 

 the phylogeny of living beings, and this is a matter that usually 

 appears uninteresting to those people who do not find it of interest. 



Enormous advances in the study of morphology have taken 

 place during the past two decades, largely as the result of the 

 development of the electron microscope. 



It is now reasonably clear that surveying the whole of animate 

 nature, we can make a fairly good initial dichotomy into those 

 organisms which lack a multistrand flagellum, true mitochondria 

 and chromoplastids, and those in which one or more of such 

 structures are found. 



For the first group we may use, following current practice, if 

 not strict priority of usage, the term Monera, and regard the 

 group, following an old convention in nomenclature, as a kingdom. 

 The Monera are presumably divisible into at least four major 

 groups. Of these the Eubacteriae and Spirochaetae are essentially 

 swimming organisms, to use Pringsheim's (1949) convenient term, 

 in which a flagellum quite unlike that of the members of the 

 higher kingdoms may be developed. The Myxophyceae and the 

 Myxobacteriae are in contrast gliding organisms. Some modern 

 authorities (e.g., Stanier, 1959) are clearly on the point of making 

 two phyla, one for the swimming and one for the gliding forms, 

 but no names have been given. There is unfortunately nothing to 

 hint which group is the more primitive. Also some organisms are 

 still incertae sedis and are hard to discuss briefly because they 

 seem to lack properly established names. The most important 

 form a group including the causative organism of bovine pleuro- 

 pneumonia, Asterococcus mycoides. Apparently allied to this is a 

 very distinguished type of organism originally isolated from 

 sewage by Laidlaw and Elford (1936) and subsequently found in 

 soil (Seiffert, 1937), which has been called, though perhaps in- 

 validly, Sapromyces laidlawi Sabin. It is of immense theoretical 

 significance because it is apparently the smallest free-living 

 organism yet known, having during the early part of its life 



