ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 553 



Annulata. 



Antarctic and Sub-antarctic Chsetognatha.* — G. Herbert Fowler 

 reports on three species of Chfetognatha collected by the ' Discovery ' 

 south of 4:0° S., viz. Sagitta hexaptera D'Orbigny, S. serrato-d&ntata 

 Krohn, and Krohnia hamata Mobius. In a collection made by the 

 ' Challenger ' he found the same species, with the addition of S. zetesios 

 Fowler. He notes that Krohnia hamata ranges from 81° 30' N. to 

 77° 49' S., that S. hexaTptera is pantothermal and cosmopolitan, and that 

 S. serrato-dentata was absent at the colder stations of both ' Discovery ' 

 and ' Challenger.' It is not " bipolar," though found in sub-antarctic 

 and north temperate seas. 



Vascular System of Chsetopods.* — Karl Fuchs has made an 

 elaborate study of the blood-vascular system of Chajtopods, with especial 

 reference to Lumbricidje and Arenicolidae. In the former the system is 

 strictly metameric : there are no vessels free in the coelom, all are bound to 

 mesenteries, septa, or the peritoneal coverings of gut and body-wall ; the 

 vascular layers are exclusively the sub-epithelial and sub-coelo-epithelial 

 hmiting lamellae ; contractility is confined to the dorsal vessel and the 

 pericorda. In Arenicolida? the system is also strictly metameric ; the 

 two lateral vessels and the two sub-nephridials, and an unpaired sub- 

 intestinal are distinctive additions as compared with Lumbricida3 ; all 

 transverse vessels are strictly intersegmental. A blood system is absent 

 in Aphi'oditidffi, Glyceridaj, Capitellidee, Polycirrin^e. The author 

 discusses the intestinal vascular plexus or blood sinuses, the ventral 

 vessel, the dorsal vessel, the connecting vessels and pericorda, the 

 supra- and sub-oesophageals and intestinals, the extra-oesophageal, the 

 sub-neural and extra-neural, the sporadic vessels, and shows how they 

 are represented in the various families. Contractility is localised in the 

 enteric blood-sinus and dorsal vessel, in the pericorda in Oligochffits and 

 Arenicohdaj, in the circum-oesophageals of Opheliidte, in the dorso- 

 laterals of Cirratulidfe, in the ventro-branchials of Eunicidfe. The 

 elaborate paper is finely illustrated. 



Polian Tubes of Sipunculus.J — F. Ladreyt has studied the histology 

 and function of these bodies. There is a dorsal and a ventral differing 

 histologically, especially in their ventral parts. Typically the polian 

 tubes consist of a muscular layer and of an internal epithelium partly 

 ciliated. In the anterior part of the tubes the ventral region is filled by 

 strands of connective-tissue. In the meshes of this lacunar connective- 

 tissue there is protoplasm with abundant nuclei. Here there are blood- 

 corpuscles in different stages of development and of ciliated urns. The 

 hinder section of the ventral polian tube is distinguished by the fact 

 that in it degeneration processes go on both in the blood-corpuscles and 

 phagocytes, as also in the connective-tissue elements. Brownish granules 

 are formed which give uric acid reactions. The front part of the dorsal 

 tube is lymphogenic, the posterior is excretory. From the latter uric acid 



* National Antarctic Expedition, iii. (1907). Chfetognatha, 6 pp., 1 chart, 

 t Jen. Zeitschr. Naturw., xlii. (1907) pp. 375-48'4 (12 pis. and 11 figs.). 

 X Arch. Zool. Exp6r., Notes et Revue. 1905, pp. 215-22. See also Zool. Centralbl. 

 xiv. (1907) pp. 105-6. 



