ZOOLOGY AND BOTaNY, MICROSCOPY, ETC. 579 



foot-tnbercle nor marginal gland, nor oesophageal glandular groove, nor 

 special shell-making epithelium. The shell is three-layered. The 

 salivary gland of Trochita is made up of flakes ; in the others tliere are 

 knob-like saccules. The stomach has a cuticular and a ciliated portion, 

 (rranular cells and club-cells occur in the liver, but no calcareous cells. 



All Calyptrasids are protandrous hermaphrodites. All have hair- like 

 and vermiform spermatozoa. All have a nephridial gland in connexion 

 with the auricle. . There is no pericardial gland. The penial nerve 

 springs from the right pedal ganglion ; the right mantle nerve springs 

 from the right pleural ganglion ; the spindle-muscle nerve is a twig 

 from the right mantle nerve ; the branchial nerve comes from the supra- 

 intestinal ganglion. There is only a small visceral ganglion. There 

 are no rods in the retina. The visual cells are pigmented. There is 

 only one statolith in the statocyst ; the latter is composed of sensory 

 cells and " Isolierzellen." In Trochita the median ridge of the osphra- 

 dium has only one row of lamellae : in other Calyptraeids there are two 

 rows. 



S. Liamellibranchiata. 



Structure of Erycinidse and CarditidaB.* — Josef Kasper has studied 

 the small bivalves Gyamium antarcticum, Kellya bullata, Lepton ijlatei, 

 and two species of Cardita, whose structure has been hitherto very 

 imperfectly known. He deals with skin and mantle, foot, alimentary 

 system, excretory system, nervous system, and so on. 



Arthropoda. 

 o. Insecta. 



Development of Insects.f — Henrik Strindberg has made an import- 

 ant study of the development of Eutermes rotundkejos^ various ants, and 

 a beetle (Chrysomela hyper ici). The course of events in the somewhat 

 low Termite type is contrasted with that in the highly evolved ant and 

 beetle types. The author describes in detail the ovum, the formation 

 and differentiation of the blastoderm, the embryonic membranes, the 

 germinal layers, the nervous system, the endoskeleton of the head, the 

 tracheal system, the oenocytes, the glands, the coelom, the metamerism, 

 the vascular system, the fatty bodies, the alimentary system, the peri- 

 trophic membrane, the Malpighian tubules, and the gonads. 



Size of Nuclei in Cells of Drones and Workers.^ — Maria 

 Oehninger has carefully compared the nuclei of the cells of drones and 

 worker-bees, in order to discover whether there is any appreciable 

 difference in size, such as that which obtains between larval Echinoids 

 with diploid nuclei (normal fertiUzation) and those with haploid nuclei 

 (merogony). The Qgg which develops into a drone starts with sixteen 

 chromosomes ; the %^g which develops into a worker starts with thii'ty- 

 two ; and one might expect the nuclei of the drone's cells to be smaller. 



* Zool. Jahrb., 1913, Suppl. 13, pp. 544-625 (31 figs.), 

 t Zeitschr. wiss. Zool., cvi. (1913) pp. 1-227 (71 figs.). 

 X Verb. Phys. Med. Ges. Wurzburg, xlii. (1913) pp. 135-40 (4 pis.). 



2 Q 2 



