PROTAMCEBA. 



[ 639 ] 



PROTOCOCCUS. 



BIBL. Berkeley, Brit. Flor. ii. pt. 2. p. 

 297. 



PROTAMCE'BA, Haeckel. A genus of 

 Protista. 



Char. A simple shapeless protoplasm- 

 bodv without vacuoles, with simple pseudo- 

 podia, not ramifying nor anastomosing ; re- 

 production by fission. 



Species. Protamceba primitiva. Proto- 

 plasm-body of 0-03-0*05 millim. diameter, 

 continually varying in form, with one or 

 several (3 to 6) peripheral pseudopodia. 

 Processes short, rounded, obtuse, finger- 

 shaped, at most as long as the diameter of 

 the central body. Freshwater, near Jena. 

 (Haeckel, Gen. Morphol. 1866, i. 133.) 



PROTEA'CE^E. -A family of Dicotyle- 

 donous plants, mostly from New Holland 

 or the Cape, shrubs or small trees (Banksia, 

 Grevillea, Hakea, &c.), of remarkably rigid, 

 evergreen habit. The coriaceous leaves are 

 well suited for the study of the epidermal 

 structures; and the stomata have interesting 

 peculiarities (see STOMATA). The epider- 

 mis is often scurfy with scattered hairs, 

 some of which are of curious forms (PI. 28. 

 fig. 29). 



PROTEONTNA, Williamson. A simple 

 Arenaceous Foraminifer ; a feeble Lituola of 

 the Haplophragmium group. 



BIBL. Williamson, For am. 1 j Carpenter, 

 For. 309. 



PROTEUS. An old name applied to 

 certain Infusoria, as Amoeba &c. Also a 

 genus of Amphibia with large blood-cor- 

 puscles. 



PROTHAL'LUS on PROTHALLIUM. 

 The structure resulting from the germi- 

 nation of the spores of the Cryptogainia, in 

 which the female, and sometimes the male 

 organs are formed. See MARSILEACE.E, 

 LYCOPODIACEJE, EQUISETACEJE, and FKKNS. 



PROTISTA, Haeckel. A kingdom of 

 organic nature supposed to be intermediate 

 between the animal and vegetable king- 

 doms, and comprising the so-called lowest 

 forms of life. It is divided into the follow- 

 ing groups : 



/ 1. G-ymnomonera (Protogenes, Pro- 

 tamceba, &c.). 



I. Monera. -< 2. Lepomonera (Protomonas, Vavfi- 

 pyrella,Protomyxa,Myxastrum, 

 ( &c.). 



/I. Nudiflagellata (Euglena, Spon- 

 TT KMo/roii fa J dylomorum, &c.). 



II. Flagellate... 2 Cili * flagellata (/^YKnfrm, Ce- 



(. ratium, &c.). 



III. Labyrinthulea (Ldbyrinthula). 



IV. Diatomea (Bacillaria). 



VIII. Protoplasta (Amoeboida).* 



{1. Chrysococcacea (Glce- 

 ocapsa, Merismopce- 

 dia, &c.). 

 2. Oscillarinea (Nostocha- 

 cea,Rivulariacea, &c.). 



1. Phycomycetes (Saprolegniece , Mu- 



corinece, &c.). 



2. Hypodermiee ( Uredince, Ustilagince, 



VI. Fungi, -j g Basid'iomycetes (Hymenomycetes , 



Gastromycetes, &c.). 

 4. Ascomycetes (Protomycetes, Disco- 

 \ mycetes, &c.) 

 VII. Myxomycetes (Mycetozoa). 



/I. Gymnamcebae 



(Autamaba, &c.). 

 2. Lepamcebae (Ar- 

 cella, Diffiugia, 

 &c.). 



3 G-regarirse 

 ^ (Grregarina) . 

 IX. Noctilucee Noctiluca. 



(I. Acyttaria (Monothalamia and 



Polythalamia). 

 X. Eliizopoda. -| 2. Heliozoa (Actinosphcerium'). 



3. Eadiolaria (Monocytharia and 

 ( Polycytharia). 



BIBL. Haeckel, Gen. Morph. ; Mon. Mo- 

 neren, Jenai. Zeit. 6. iv. 1 ; Biol. Studien, 

 1 ; Wright and Kirby, Qu. Mic. Jn. 1869 & 

 1871 ; Kent, Inf. 44. 



PROTOCOC'CUS, Ag. A genus of Vol- 

 vocineae (Confervoid Algae), at present very 

 imperfectly known, since without a toler- 

 ably complete history of the development 

 of the forms it is impossible to distinguish 

 the true species of Protococcus from the 

 young states of the more complicated Pal- 

 mellaceaB, and even from the germinating 

 gonidia of the Lichens. As we have limited 

 it, Protococcus includes those unicellular 

 Algae which in the aquatic state consist of 

 single zoospore-like bodies, with a more or 

 less evident gelatinous cellulose envelope 

 through which the two cilia protrude. 

 They move actively, and are multiplied by 

 division during the active state. Finally 

 they settle down into a resting-stage j and 

 they may then increase by vegetation so as 

 to form granular patches. Mostly, however, 

 those which settle down turn red and ac- 

 quire a thick coat, passing through a stage 

 of rest before they germinate again, appa- 

 rently requiring to be dried up first. When 

 they germinate, they frequently produce 

 many generations of still forms before the 

 active ciliated forms reappear, especially 

 when placed on damp surfaces, and not in 

 water. When placed in favourable circum- 

 stances, the resting-f orms (even after several 

 years) recommence the course of vegeta- 

 tion, reacquiring the green colour by de- 

 grees in the course of several generations of 

 vegetative cells. The contents of the red 



