lO SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 



In a group as highly variable as the planktonic Foraminifera it is 

 perhaps inevitable that opinions will vary as to the morphologic limits 

 of species. Some workers vv^ill tend to split more finely than others, 

 and in the absence of quantitative treatments of population structures 

 and the lack of data on the biology of the animal, judgments on the 

 limits of species are bound to be subjective. The poHcy here has been 

 to group together in a single species those forms that occur together 

 with intermediaries among which no line of demarcation could be 

 perceived. Admittedly, further taxonomic refinements are possible, 

 but it is believed that with the morphologic limits recognized here, an 

 internal consistency in identification has for the most part been main- 

 tained and further refinements would not significantly change the 

 distributional patterns presented. The specimens used for illustration 

 were chosen to show the range of forms included in the species, and 

 the descriptive remarks under the species refer to the specimens 

 actually examined, with the emphasis on those characters that were 

 found particularly useful for identification. 



Generic as well as specific characters are variable in the planktonic 

 Foraminifera, and some species include end forms showing close af- 

 finities to species placed in other genera. In fact, Glohigerina inflata 

 shows a transition from Glohigerina to Glohorotalia. Such continuous 

 variability across established generic boundaries suggests that the Re- 

 cent planktonic Foraminifera comprise a closely related group. There- 

 fore, they are included here in a single family, the Globigerinidae. 

 The species are grouped into eight commonly recognized genera, 

 though, admittedly, the genera serve in some cases, owing to a lack 

 of exclusive characters, more as conveniences than as representations 

 of genetic affinities. 



In the use of specific names an attempt has been made to conform 

 with the present Code of Zoological Nomenclature ( 1961 ) . As pointed 

 out by Todd (1961, 1963) this code now limits the application of 

 priority in the naming of species. However, it is not clear from the 

 provision of conservation (article 23b) what these limitations are, 

 and, in fact, there is some question as to whether that provision can 

 actually be interpreted. Therefore, it would appear that the code 

 serves as a guide rather than a "cook book," and the individual is not 

 relieved of the responsibility of exercising individual judgment in 

 serving the interests of nomenclatural stability. As a result, some 

 arbitrary decisions were found necessary in the choice of names, and 

 these are discussed under the species concerned. 



