ZOOLOOY AND BOTANY, MICKOSCOPY, ETC. 203 



full description is given. There is a useful diagnostic key of American 

 species. 



In another paper Ash worth* reports on the collection in the Paris 

 Museum, which includes A. marina, A.grubii, A.ecaudata, and A.pusilla 

 Quatrefages. Of the last a description is given. 



Arenicola loveni.t — J. H. Ashworth gives an account of A. loveni 

 Kinberg from Durban and Saldanha Bay. Its systematic position may 

 be stated thus — there is no affinity beyond a generic one between it and 

 A. claparedii, A. assimilis, and A. glacialis. In general appearance it 

 most nearly resembles the large Laminarian examples of A. marina, 

 but in its prostomium and setas, and in some of its internal organs, 

 especially its septal pouches and statocysts, it departs markedly from 

 A. marina and much more nearly approaches A. cristata, from which it 

 differs chiefly in the number of its segments and gills. These facts 

 indicate that the affinities of A. loveni lie between A. marina and 

 A. cristata, but more closely to the latter than to the former. The median 

 lobe of the prostomium is large ; neuropodia are clearly visible on each 

 segment ; each notopodial seta bears numerous finely toothed crests at 

 regular intervals along the distal third of the shaft ; there are two 

 enormous muscular pouches projecting backwards from the first septum, 

 passing through the second, and ending immediately in front of the 

 third ; the two statocysts are closed oval sacs, each containing a large 

 oval secreted statolith. 



Precision of Regeneration in Polynoids.J — Aug. Michel has experi- 

 mented with Halosydna gelatinosa and Lagisca extenuata, which are 

 very readily provoked to autotcmy of segments and elytra. The striking 

 fact which he brings out is the absolute precision with which the normal 

 number of elytra, which alternate in twos or in threes, is preserved in 

 the regeneration. 



"» v 



Sansilli and Eyes of Medicinal Leech. § — L. Hacklov gives an 

 account of the sensilli or unspecialized sensory cells of the leech, which 

 respond to all sorts of stimuli, and shows how by their specialization in 

 one direction they have given rise to eyes, and in another direction to 

 olfactory organs. There can be no doubt that the eyes of Hirudo are 

 highly organized results of the evolution of touch-organs. 



Chaetognatha from Ireland. [| — Rudolf von Ritter-Zahony finds that 

 in the upper layers off the Irish coast this group is almost solely repre- 

 sented by Sagitta bipunctata and Spadella cephaloptera. There is a com- 

 paratively rare occurrence of Sagitta serratodentata, and of younger stages 

 of EuTcrohnia hamata. A very different state of things prevails as regards 

 the Chaetognaths of the mesoplankton ; Sagitta bipunctata and Spadella 

 cephaloptera are entirely absent ; Eukrohnia hamata predominates, and 

 with it we have nine additional species, of which some are permanently 



* Ann. Sci. Nat. (Zool.), 1910, pp. 111-24 (4 figs.). 



t Arkiv Zool., vii. (1909) No. 5, pp. 1-17 (1 pi.). 



\ Coniptes Rendus, clii. (1911) pp. 152-3. 



§ Zool. Jahrb., sxx. (1910) pp. 261-300 (4 pis. and 3 figs.). 



|| Fisheries Ireland Sci. Invest., iv. (1910) pp. 1-7. 



