472 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Porifera. 



Sponges from Malaga.* — Francisco Ferrer Hernandez contributes 

 some notes on interesting sponges from Malaga : — Geodia cydonium, 

 Ficulinaficus, Hymeniacidon mammeata, Ciocalypta peniciUus, ffalkhon- 

 dria albescens, Reniera densa, and Sponf/elia elegans. 



Protozoa. 



Structure of Myonemes.f— G. Roskine has studied in particular the 

 myonemes of Stentoi- coeruleus. Each contractile element lies in a canal 

 with granular walls, relatively soHd and elastic. The space between the 

 walls of the canal and the myoiieme itself contains a fluid. The plasma 

 of the myoneme shows in life a hardly perceptible fibrilloid structure, 

 which may suddenly resolve itself into drops. It is probable that the 

 myoneme has a delicate solid membrane surrounding a contractile fluid 

 kinoplasm. In Climacostomiwi, which is allied to Stentor, the myonemes 

 have become solid, elastic, non-contractile cy to-skeletal filaments. 



Mitochondria in Protozoa. | — A. Alexeiefi" finds that all the differen- 

 tiations in the cytoplasm of Protozoa are due to mitochondria. They 

 are the formative " plasts," as in Metazoa. In some cases they have 

 a nuclear origin, and are not to be separated oft" from chromosomes and 

 chromidia. Like chromatin bodies, they can multiply at the expense of 

 materials furnished by the cytoplasm. Even in cases like Blastocystis 

 enterocmla, where the mitochondria seem to be independent of the nucleus, 

 they may be regarded as pbylogenetically dependent, as are also blepharo- 

 plasts. Cytoplasmic differentiation in general has a nuclear origin ; the 

 nucleus has a profoundly important morphogenic role. The large 

 complex molecule of nuclear substance seems to give rise in the cytoplasm 

 to much simpler substances, like lipoids, glycoplasts, amyloplasts. The 

 parabasal body of Flagellates is to be ranked with glycoplast mito- 

 chondria. Flageila and cilia are to be referred back to the nucleus, with 

 the blepharoplast as intermediary. 



Mitochondria and Parabasal Body of Flagellates.§— A. Alexeieff 

 advances reasons for regarding the parabasal body as mitochondrial in 

 nature. In Trypanosoma the mitochondria are primarily situated in a 

 vacuole in front of the kinetonucleus, and are afterwards diffused in the 

 cytoplasm ; the parabasal body is known as the kinetonucleus. In Bodo 

 the parabasal body or kinetonucleus gives off siderophilous granules, 

 probably glycoplast mitochondria, which form a chajalet. In Cryptohia 

 the mitochondrial granules form a row along the undulating membrane. 

 In a species of Bicosceca, Prowazek has described a single chromidium. 



* Boll. Soc. Espaii. Hist. Nat., xvii. (1917) pp. 228-90. 



t C.R. Soc. Biol. Paris, Ixxx. (1917) pp. 363-4. 



X C.R. Soc. Biol. Paris, Ixxx. (1917) pp. 361-3. 



§ C.R. Soc. Biol. Paris., Ixxx. (1917) pp. 358-61 (15 figs.). 



