/OOLOGY AND BOTANY, MICROSCOPY. ETC. 18 1 



Structure of Haplodiscus.* — W. Salensky describes certain parts of 

 this interesting and very primitive representative of the Turbellaria 

 Acoela. The subject of his study was H. ussoivii from Messina and 

 Naples. The parenchyma is discussed in detail. The central paren- 

 chyma consists of two epithelial layers, a dorsal and a ventral, which 

 meet in the horizontal plasma ; these two layers correspond to the 

 dorsal and ventral walls of the alimentary canal of other Turbellaria ; 

 the oral or digestive parenchyma is a part of the central parenchyma 

 and presumably of endodermic origin. The frontal organ is an aggre- 

 gate of skin-glands opening at the anterior tip of the body ; the secretion 

 is probably offensive and defensive. Delage's suggestion that the organ 

 is sensory is not, however, dismissed, for a strong nerve passes to the 

 organ from the brain. The post-cerebral cell-mass is very like an 

 aggregate of ovarian cells, but it seems to have no connection with the 

 gonads, and is probably glandular. The vas deferens and the seminal 

 vesicle are described. 



Incertae Sedis. 



New Species of Myzostoma.t — J. F. McClendon describes three new 

 species — M. cubanum, M. evermanni, and M. cerriferoideum, found on 

 Crinoids and Ophiuroids in the Smithsonian Institution. Previously J 

 he gave an account of those collected on the ' Albatross ' expedition to 

 Japan. 



Notes on some British Polyzoa.§ — A. M. Norman discusses Micro- 

 pora impressa (Moll.) from Guernsey, Terebripora ditrupm sp. n. from 

 the calcareous shell of the Annelid genus Ditrupa from Shetland, Schizo- 

 porella alderi (Busk) which show considerable variation in its mode of 

 growth, Eschariaa dutertrei (Audouin), Phylactella pygmc&a (Norman) 

 from Shetland, of which a figure is given for the first time, and Gellepora 

 surcularis (Packard). 



Genus Aucella.|| — A. P. Pavlow gives a monographic account of 

 this Brachiopod genus, discussing the relationship and distribution of 

 the numerous species, and taking account of Aucellina and other related 

 types. 



Rotifera. 



New Rotifera.^f — C. F. Rousselet gives a description and figures of 

 Brachiotius sericus, a new species characterised by the structure of the 

 lorica, which is covered all over with fine longitudinal wavy lines giving 

 the appearance of watered silk, and also by a posterior overhanging, 

 more or less pointed, projection of the carapace. The author further 

 describes Brachiomis quadratus var. rotundas, a new variety, and gives 

 accurate figures of Brachiomis rubens Ehrenbg., which appears to have 

 been wrongly figured and described in Hudson and Gosse's monograph. 



* Bull. Acad. Soi. St. Petersbourg, No. 18 (1907) pp. 819-42 (8 figs.). 

 + Proc. U.S. Nat. Museum, xxxii. (1907) pp. 63-5 (2 figs.). 

 % Bull. Amer. Mus. Nat. Hist., xxiii. (1906) pp. 119-30 (3 pis.). 

 § Ann. Nat. Hist., xx. (1907) pp. 207-12 (1 pi. and 1 fig.). 

 || Nouv. Mem. Soc. Imp. Nat. Moscou, xvii. (1907) pp. 1-84 (6 pis.). 

 ^ Journ. Quekett Micr. Club, (1907) pp. 147-54 (2 pis.). 



