108 JOURNAL OF THE [October^ 



from the domain of the Protozoa. I have consulted as many 

 sources of information as the limited literary resources of my 

 surroundings would admit. 



First of all, possessing a copy of Joseph Leidy's " Rhizopods 

 of North America," I consulted that for a portion of my data. In 

 the said monograph is a general account of the classification of 

 the Protozoa and their characteristics, as adapted from the greaf 

 work of Prof. Haeckel. In this I find that, of the true Rhizopoda 

 alone, the following species are characterized as having a proto- 

 plasm capable of secreting silicious shells, skeletal coverings, or 

 external appendages — \\z., Euglypha alveolata and Euglypha olex; 

 Clathuralina elegansj Acafithocystis (minute silicious spicules); 

 Challengeria (single-celled silicious organisms); Acanthometrina 

 (having its spicules arranged in geometrical patterns, such as 

 might be developed in a space of three dimensions, or on the sur- 

 face of a sphere, and, owing to their extreme delicacy, collapsing 

 or falling apart on drying and handling, and which were appa- 

 rently only found in the material dredged by the C/ialletiger); and 

 also the Thallasicola, together with the numerous genera of the 

 Radiolaria. 



In connection with these I would refer to the fact that the 

 peculiar open-meshed and stellate silicious skeletons known as 

 Dictyocha, hitherto classed with the diatoms, likewise the forms 

 called Eucainpia, are stated in WoUe's " Diatomaceae of North 

 America" to be no longer regarded as diatoms, but are excluded 

 therefrom. This dictum would relegate them to the Protozoa. But 

 they are nearly always present in recent as well as fossil diatoma- 

 ceous earths, as I have put upon record in the Journal of the 

 Society in some remarks upon a small Navicula didyma overlap- 

 ping a Dictyocha fibula in the body of a Coscinodiscus from the 

 Tampa fossil earth slide, filed with and donated to the Society. 

 What expert diatomist will undertake to clear up the puzzle pre- 

 sented by the fifty or more discoidal forms on the same selected 

 slide, exhibiting, either upon or through the internal structure of 

 the diatom, hundreds of minute diatoms of many distinct species 

 held therein ? How did they get there, and why was the selec- 

 tion limited exclusively to the minutest of forms ? Has any one, up 

 to the noting of this peculiar characteristic of the discs of the 

 Tampa marine fossil earth, made any observation of a similar con- 



