174 THE MASTIGOPHORA 



TRIBE 1. CHLOROMONADINA, Klebs. 



The body is naked, the periplast consisting of a smooth non-resistent 

 membrane formed by a thick layer of ectoplasm, in place of the in- 

 tegument of the Euglenoids. The chloroplasts are generally numerous 

 and the vacuole-system is compound, resembling that of the Euglenoids. 

 The product of metabolism is neither starch nor paramylum, but fatty 

 oil. There is a funnel-shaped depression at the base of the flagellum 

 corresponding with the cytostome, but not used for the ingestion of food. 



Genera Vacuolaria, Cienkowski ; Coelomonas, Stein; Raphidomonas, 

 Stein. 



TRIBE 2. CHRYSOMONADINA, Biitschli. 



The members of this tribe resemble the Protomastigina, with the 

 addition of chromatophorea which carry a yellowish-brown pigment called 

 chrysochrome, allied to diatomin. The chrysochrome-plates are usually 

 two in number, placed right and left. They do not contain pyrenoids 

 and do not manufacture starch. There is a red stigma (eye-spot). The 

 products of metabolism are fatty oil and a refringent soluble proteid 

 called leucosin (Klebs). 



Nutrition is generally holophytic ; there is no mouth ; generally two 

 flagella. 



The tribe is divided by Klebs into three sections or sub- tribes : 



A. CHRYSOMONADINA NUDA. 



Chrysamoeba, Klebs; Chromulina, Cienkowski ; Ochromonas, Vyssotzki; 

 Stylochrysalis, Stein. The last-named is attached to colonies of Eudorina. 



B. CHRYSOMONADINA LORICATA. 



Dinobryon, Ehrenberg (Fig. 5 (8, 15)) ; Hyalobryon, Chrysopyxis, Ehrb.; 

 Chrysococcus, Klebs ; Cyclonexis, Senn. 



The researches of Lohmann (11) have shown that the family 

 Coccolithophoridae must be included in this group. 



The members of this family are extremely minute organisms, 

 of which the largest species are only 25-50 /A in diameter, found in 

 the plankton of the sea and characterised by the possession of 

 a theca composed of minute calcareous shells which have long 

 been familiar to zoologists under the names " coccoliths " and 

 "rhabdoliths." 



The organism bears one flagellum or two equal flagella, a single 

 nucleus, two (rarely one) large green or brown chromatophores, 

 each containing a drop of a substance which appears to be oil 

 (Fig. 6, D), and in many cases a vacuole situated near the base of 

 the flagellum. The body is surrounded by a soft membrane which 

 supports the theca of calcareous shells. The shape of the shells 

 that compose the theca shows immense variety in the family. Two 



