170 SUMMARY OF CURRENT RESEARCHES' BELATING TO 



marine area — a fact which is easily accounted for by the rarity and in- 

 accessibility of the members composing it. He deals with Pelagobia 

 hnujccirrata Greef, P. serrata sp. n., Maupasia caeca Viguier var. atlan- 

 tica n., Haliplams magna sp. n., Lopadorhynchas appendiculatus sp. n. 



Primitive Germ-cells in Sagitta.* — W. Elpatiewsky finds that one 

 of the blastomeres arising from the fifth cleavage is the first primitive 

 germ-cell. It is marked by a particular body — taking on nuclear stains 

 — which is seen in all the germ-cell lineage. 



New Leeches from Ceylon.j — W. A. Harding describes Ozolranchas 

 shipleyi sp. n., in which the abdominal region bears eleven pairs of digitate 

 branchiae, and Glossiphonia ceylanica sp. n. The former is parasitic on 

 the terrapin Nicoria trijuga, the latter on the soft tortoise, Emydn vittata. 



Nematohelminthes. 



Nervous System of Ascaris.J — R. Goldschmidt continues his in- 

 timate analysis of the nervous system of Ascaris megalocephala and A. 

 lumbricoides. He deals with the nerve-ring and the mode of union 

 among its components, attaching numbers to the various cells and fibres, 

 so that their connections are clearly seen in the diagrammatic reconstruc- 

 tions. Pie also discusses the general problems of continuity or contiguity 

 of elements, of the neuron, and of the reflex arc, and ends up with a com- 

 parative morphological sketch of various nervous systems. His three 

 schematic plates of the Ascarid system are very remarkable achievements. 



Fibrillar Structures in Muscle-cells and Intestinal Cells of Asca- 

 rids.§ — Fr. Bilek has studied in Ascaris cam's and A. semiteres, and other 

 forms, the peculiar fibrils in the muscle-cells and intestinal cells which 

 have been called " neurofibrils," " spongioplasm," " supporting fibrils," 

 and a " chromidial apparatus." The muscle-cells are gigantic ; the thin 

 gelatinous sarcoplasm requires some support in its contraction and dilata- 

 tion. The fibrils form a kind of internal scaffolding. In the gut-cells 

 they are not only supporting elements, but they replace the absent 

 muscularis. The fibrils are essentially sarcoplasmic, not nuclear, and 

 their interpretation as chromidial is erroneous. 



Subcuticula and Lateral Areas of Nematodes. ||— E. Martini has 

 made an exhaustive study of sixteen types. Apart from the tail-end, 

 behind the muscles, where there are no longitudinal lines, the sub-cuti- 

 cula is without nuclei. These occur only in the inturnings of the sub- 

 cuticula, which are called longitudinal lines. In the trunk the dorsal 

 line is without nuclei. The ventral line shows some nuclei. There are 

 usually three rows of nuclei in the lateral area, and they may be very 

 numerous. Nuclei are never absent from the lateral line. In the head, 

 all the four main longitudinal lines show nuclei, and the tissue of the lines 

 extending inwards forms a support for the nerve-ring and nerve-centres. 



A more general statement may be useful. The epidermis of Nema- 



* Anat. Anzeig., xxxv. (1909) pp. 226-39 (19 figs.), 

 t Proc. Cambridge Phil. Soc, xv. (1909) pp. 233-4. 

 I Zeitschr. wiss. Zool., xcii. (1909) pp. 306-57 (3 pis. and 21 figs.). 

 § Op. cit., xciii. (1909) pp. 625-67 (2 pis.). 

 I| Tom. cit., pp. 535-624 (2 pis. and 21 figs.). 



