ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 71 



published. It does not contain the expected characters of the genera 

 and description of the species figured in the fi.rst part, which are still 

 further deferred, but deals with the forms most of which are more 

 usually known under the name of Cilio-flagellata, 



After a descriptive account of the course of his researches since 

 the publication of the first half in 1878, the author gives a summary 

 (in 23 pages) of the results at which he has arrived. The forms now 

 treated of he considers to be a sub-order of the Flagellata, the simpler 

 forms of Flagellates described by the first part forming the other sub- 

 order. The latter he terms Monero-flagellata and the former 

 Arthrodelo-flagellata- He objects to the name of Cilio-flagellata, as 

 it supposes that the organisms besides a flagellum are provided with 

 cilia, whilst Prorocenirum and Noctiluca are without such cilia. They 

 all, however, have a distinctly articulated body, whence the designation 

 Arthrodelo. 



The division into five families is founded upon the modifications of 

 the articulation, and the 30 genera upon the absence or presence of a 

 secondary articulation of the body-covering as well as on their arrange- 

 ment, number, form, and size. The following are the families and 

 genera : — 



Prorocentrinse (Prorocentrum, Dinopyxis, and Cenchridium), 

 CladopyxidaB (Gladopyxis), Peridinida3 (Gymnodinium, Hemidinium, 

 Glenodinium, Clathrocysta, Heterocapsa, Amphidoma, Oxytoxum, Pyr- 

 gidium, Ceratocorys, Goniodoma, Gonyaulax, Blepharocysta, Podolampas, 

 Diplopsalis, Peridinium, and Ceratiwm). 



DinophysidaB (Amphidinium, Phalacroma, Dinophysis, Amphisolenia, 

 Citharistes, Histioneis, and Ornithocercus), 



Noctilucidse (Ptycliodiscus, Pyrophacus, and Noctiluca). 



Being prevented by unfavourable weather from going to the sea, 

 Dr. Stein bethought himself of trying the contents of the stomachs of 

 marine animals preserved in spirit, and in this line of research he was 

 completely successful, by far the most numerous and important of 

 his discoveries being obtained from the stomachs of various Tunicates 

 (Ascidia, Salpa, and Cynthia'), Vermes (Sabella, Serpula, and Sipunculus), 

 and Echinoderms (Synapta, Ophiothrix, ' Comatula,' and Actinometra). 

 Hundreds of individuals were obtained from one species of Salpa, and 

 the author was occupied from November 1880 to the end of 1882 in the 

 examination of the organisms he thus found. 



A general description is given of the principal forms, with refer- 

 ences to the 25 plates, which are also accompanied by brief 

 " explanations." It was not found possible to engrave all these on 

 copper as was done in the case of the plates of the preceding Parts, 

 and 11 are accordingly lithographs. 



It will be observed that Stein includes Noctiluca in his order of 

 Arthrodelo-flagellata. His justification for this we propose to deal 

 with later, but here may be mentioned that it is based on the discovery 

 of the forms placed in the two genera Ptycliodiscus and Pyrophacus, 

 which on the one hand are closely related to Noctiluca while on the 

 other they are unmistakably Arthrodelo-flagellates. 



