396 PROF. ALLMAN ON THE EECEKT RESEAUCHES 



thick and finger-shaped and, like those of Syalosphenia, enclose 

 fine granules. 



In the fact of its shell being composed of numerous juxtaposed 

 plates Quadrula presents an obvious affinity with Euglypha, from 

 which, however, its compressed form and, above all, its thick finger- 

 shaped pseudopodia clearly separate it. In tests from which the 

 protoplasm has disappeared detached plates similar to those com- 

 posing the walls are frequently found either lying free or associated 

 in bundles. A fact of quite a similar kind has been noticed in 

 Euglypha. 



Hertwig and Lesser have studied the DifflugioB and have de- 

 scribed a new species {D. acropodia) remarkable for the peculiar 

 form of its pseudopodia, while they bring together the essential 

 characters of the genus more exactly than had been hitherto done. 

 The genus Biffiugia was founded by Leclerc for freshwater TTia- 

 lamopTiora with blunt pseudopodia, and whose test provided with 

 a single opening is not a pure excretion of the protoplasm, but is 

 formed of agglutinated foreign corpuscles — fragments of silica and 

 shells of Diatomacea. The shell so constructed, however, has, as 

 the new species examined by Hertwig and Lesser clearly shows, 

 a membranous basis excreted by the contained protoplasm. 



The Difflugice have a nucleus immersed in the posterior part of 

 the protoplasm ; but no contractile vesicles have as yet been dis- 

 covered. Like the Heliozoa they contain also in their protoplasm 

 chlorophyl-granules, a fact of extremely rare occurrence among 

 the ThalamopJiora. 



In D. acropodia the pseudopodia differ from the finger-shaped 

 processes of other Dvffiugice in consisting of broad plates of homo- 

 geneous protoplasm, which at some distance from the pseudopodial 

 opening end in irregularly-shaped lobes with their contours cut 

 into sharp segments. They owe their origin to the confluence of 

 what were at first narrow lancet-shaped pseudopodia very like 

 those of ActinospJicBrium, except in being destitute of granules. 

 They form an obvious transition between tlie blunt pseudopodia 

 of the Lohosa, and the pointed pseudopodia of those forms to 

 which Hertwig and Lesser would confine the name of RMzopoda, 

 the Filifera of P. E. Schulze. 



The siliceous fragments with which the test is set are usually 

 so sparingly scattered as to reveal the thin basal membrane on 

 which they are fixed. 



The Thalamopliora with pointed filiform pseudopodia {Filifera) 



