196 PROTOZOA. 



solid nutriment. The best known genus is Euglena, which, according 

 to Stein, has a mouth and gullet. 



In their inactive stage they secrete a capsule and divide up into 

 parts which pass out as mastigopods. Euglena viridis (fig. 134), E. 

 sanguinolenta. Another genus, also with a mouth, is Astasia Ehrbg. 

 A. trichophora Ehrbg., with rounded posterior end, a very long flagel- 

 lum, and an abruptly terminated anterior end. 



The genera Salpingoeca and Codosiga described by Clark were 

 included by Biitschli under the name Cylicomastiges, on the ground 

 that they possess a well-marked collar surrounding the basis of the 

 nagellum, and corresponding to the collar on the entoderm cells of 

 the Sponges (hence Clark regarded the Sponges as most nearly 

 related to the Flagellata); Codosiga Botrytis Ehrbg, forming 



colonies, possessing food vacuoles 

 which contain the solid bodies taken 

 up as nutriment, with nucleus and 

 contractile vacuole. 



Salpingoeca Clarkii Biitsch. (the 

 individuals of this species possess a 

 shell). ' 



Another group, the Cilioflagel- 

 lata* is characterised by the posses- 

 sion of a row of cilia, situated in a 

 furrow of the hard cuticular exo- 

 FIG. \tt.-Ceratium tripos (after skeleton (fig. 135), in addition to 

 Nitzsch). the nagellum. The Peridiniw, some 



of which are of peculiar appearance, 



with large horned processes of the shell, belong to the group, and are 

 allied, so far as their development is know r n, most nearly to the 

 Euglence. The mouth lies in a depression ; there is sometimes a 

 kind of gullet, at the end of which the nourishing materials pass 

 into a vacuole. In addition to the locomotive and armoured forms, 

 there are also some without shell or organs of locomotion ; and again 

 there are encysted stages in the interior of which a number of small 

 young forms are said to take their origin (Ceratium cornutum Perhg., 

 Peridinium tabulatutn Ehrbg). 



Finally Noctiluca t is included in this group. It is an inhabitant 



* R. S. Bergh, " Der Organismus der Cilioflagellaten," Morpli. Jahrb. Tom. 

 TIL 



L. Cienkowski, " Ucber Noctiluca miliaris" Arclriv. fur microsh. Ana* 

 tomie, 1871 and 1872. 



