AMONG SIMPLE SARCODE OEGAKISMS. 4<oo 



tional stages iu the development of some other Mouera (Profo- 

 myxce) as well as in that of the Grregarinse. But the Frotamcebcs 

 of Haeckel are independent organisms directly reproducing them- 

 selves by spontaneous fission. The forms constituting the genus 

 Protamceba are thus distinguished from the other Monera by their 

 simple pseudopodia, which never anastomose with one another so 

 as to form net-like expansions, and also by the fact that their 

 reproduction is by simple self-division without this being pre- 

 ceded by an encysted or resting state. A similar form of repro- 

 duction exists in Protogenes, another genus of Monera ; but here 

 the pseudopodia are long thin branching processes which anasto- 

 mose with one another and form protoplasm-nets. 



Fiff. Ifi. 



ProtcmuBha primitiva. 



A, the Protamceba with short lobe-like pseudopodia. B, the same, with a 

 longer pp'^udopodium. C, the same, in the act of self-division into two segments 

 («, h). (After Haeckel.) 



Besides Protamoeba primitiva, several other species of Protamceba 

 have been since described by Haeckel*. 



A peculiar slimy substance dredged from depths of from 5000 

 to 25,000 feet in the Atlantic Ocean, during the exploring expe- 

 dition of the ' Porcupine,' had been examined by Huxley, who 

 concluded that it consists of living protoplasm, vast masses of 

 which extend over wide areas of the sea-bottom. He assigned to 

 this remarkable substance the name of Bathybius. 



Associated with it and imbedded irregularly in the slime are 

 certain calcareous concretions of a very definite shape. These 

 have been named Coccoliths by Huxley. They are in the form 

 either of simple disks (Discoliths), or of two such disks united to 

 one another so as to form a body (Cyatholith) whose shape has 

 been very aptly compared by Huxley to a shirt-stud. Besides 

 * "Nachtrage zur Monographie der Moneren," Jen. Zeit. 1871. 



LINN. JOUEN. — ZOOLOGY, VOL. XIII. 36 



