ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 591 



Echinoderma. 



Genus Astropecten.* — L. Doderlein gives a detailed account of this 

 :genus, with great wealth of illustration of the spines and plates. He 

 deals with eighty-five species, thirteen sub-species, and six varieties ; of 

 these forms he has himself investigated seventy-seven ; there are twenty- 

 three new species and sub-species. A " seriventral " group, with numerous 

 ventro-lateral plates in several well-developed lateral rows, is represented 

 by A. schat/eri &Tp. n. A " pluriventral" group, with three to thirteen 

 ventrolateral plates in one longitudinal row, is represented by such forms 

 as A. aranciac'us and A. irregularis. A "biventral" group, with only 

 two ventral plates, is represented by such forms as A. polyacanthus and 

 A. vappa. A full discussion is given of the various kinds of plates, 

 spines, and paxilla?, and of the tufted pedicellarige. The most primitive 

 forms belong to the schayeri group, e.g. A. schayeri, A. mesadus, and 

 A. sphenoplax, and from these the lines of evolution within the genus 

 ■are traced. 



Coelentera. 



Genus Antenella.t— M. Bedot discusses this genus of Hydroids, 

 recognizing two groups of species. In group A there are two pairs of 

 pleurohydrothecal nematothecre ; on each side the nematotheca of the 

 first pair is fixed on the summit of a peduncle which carries near its 

 base the nematotheca of the second pair. In group B there is a single 

 pair of pleurohydrothecal nematotheca^. But this grouping is not in- 

 tended as more than provisional, to facilitate the comparison of species. 



South African Gorgonacea.J— J. Stuart Thomson completes his 

 account of these Alcyonarians, and records twelve new species : — 

 Anthothela parviflora, Melitodes faurii, M. grandis, MopseUa singularis, 

 Wrightella trilineata, W. frag His, W.furcata, Stachyodes capensis, Lepio- 

 gorgia africana, L. aurata, Eugorgia lineata, and Stenogorgia capensis. 

 There are some excellent coloured figures and numerous drawings of 

 spicules. 



Porifera. 



Reproduction and Development in Grantia compressa.§ — Olga 

 M. Jorgensen finds that the breeding season of this Purse Sponge is on 

 the Northumberland coast from June to the beginning of September- 

 At Plymouth, according to Orton, breeding begins in xipril ; embryos, 

 are freed in June ; there is a later reproduction from the year's larvae in 

 August ; and disintegration occurs in autumn. 



The ova are unusually large ; there are two maturation divisions ns 

 usual ; segmentation is total and equal as far as the seventh or eightli 

 division, after which a small number of cells at one pole increase in 

 size, become more granular, and divide much less quickly than the 



* " Siboga " Expeditie, Monogrophie xlvi a (1917) 191 pp. (17 pis. and 21 figs.). 

 t Rev. Suisse Zool., xxv. (1917) pp. 111-29. 



J Mem. Proc. Manchester Lit. Phil. Soc, Ixi. (1916, published 1917) pp. 1-56 

 (5 pis. and 5 figs.). 



§ Report Dove Marine Laboratory, vi. (1917) pp. 26-31 (1 pi.). 



