282 SUMMARY OF CUJ.'KENT RESEARCHES RELATING TO 



inhibition can be prodnced by mechanical, chemical and electrical 

 stimuH. Certain nerve poisons (chloral hydrate and atropin) abolish 

 the primary inhibitory effect of a galvanic cnrrent. There are "forma-, 

 tions " which serve as cilio-inhibitory nerves, and these are paralysed 

 by the poisons. The primary cilio-inhibitory mechanism probably 

 consists of receptors at the surface of the body, which transfer their 

 impulses to a set of nerves, which transmit them to end apparatuses 

 inhibiting the vibrations of the swimming plates, probably by blocking 

 the neuroid conduction between them. The mechanism for primary 

 inhibition also functions in specimens from which the statolith apparatus 

 has been removed. There is an intimate connexion between primary 

 and secondary (i.e. muscular) inhibitory mechanism in Bero'e. It is 

 probable that they both use the same receptors, but the primary 

 mechanism can be caused to function bv impulses of a weaker intensity. 



J. A. T. 



Two Japanese Ctenophores. — Taku Komai {An not. ZooL Japon., 

 1921, 10, 15-18, 2 figs.). Descriptions of Lampetia pancerina Chun 

 and Bero'd ramosa sp. n. The latter may be distinguished from its near 

 ally Bero'e ovata by the presence of much more numerous side-branches 

 to the meridional and pharyngeal canals. J. A. T. 



New Species of Sertularella. — Ar3iand Billard {Arch. Zool. 

 Eiper., 1920, 59, Notes et Revue, 1, 14-6, 1 fig.). A description of 

 S. singularis sp. n. from the Siboga collection. It differs from all 

 other members of the genus in the irregularity exhibited in the disposi- 

 tion of the hydrothecse, showing that much stress cannot be laid on 

 this character. In the same colony and on the same branch there are 

 alternate, opposite, and verticillate (three or four) arrangements. The 

 form of the margin and the nature of the operculum must be looked to 

 as more important thaa the arrangement of the hydrothecse. In 

 Sertularella the hydrothecse are usually alternate, save in S. tamarisca, 

 where they are opposite. J. A. T. 



Silurian G-raptolites from Bornholm. — Assar Haddin& {Luncls 

 Universitets Arsskrift, 1915, 11, No. 4, 1-40, 4 pis., 4 figs.). Descrip- 

 tions of species of Diplograptus, CUmacograptus, Dicellograptus, Gorij- 

 noicles and other genera, along with some new Brachiopods and Molluscs, 

 from Dicellograptus beds at Bornholm. J. A. T. 



Protozoa. 



Flagellate Parasite of Euphorbias. — C. Fraxca {Ann. Inst. 

 Pasteur, 1920, 34, 432-65, 2 pis., 2 figs.). In the latex of various 

 species of Euphorbia, e.g. E. peplus and E. segetalis, there lives a 

 Flagellate, Leptomonas davidi, discovered by David, first studied by 

 Lafont. It is usually an elongated narrow form, twisted posteriorly 

 twice or thrice on its axis, with an elliptical nucleus and a spherical 

 karyosome, with a spherical blepharoplast bearing a delicate flagellum. 

 It divides longitudinally in the latex, and a new flagellum is formed for 

 one half. The nucleus and blepharoplast show in dividing the process 

 known as panmitosis or monopanmitosis. In the alimentary system of 



