LTONEAK 80CTETT OF LONDON. 55 



longitudinal cords united in a cephalic ganglion and by numerous 

 transverse commissures, is to be considered only as a step in ad- 

 vance upon that o£ the Planariro described by Lang. Similarly, 

 the nephridia or excretory organs appear (especially from the 

 researches of Sedgwick upon Chiton, (Proc. Eoy. Soc. 1882) to be 

 a pair of contorted tubes opening into a more or less rudimentary 

 body-cavity by one end, and to the exterior by the other. Whilst 

 these AmjDhineura furnish close points of contact with the flat 

 worms, there is no difficulty in tracing to the structures found in 

 them the special modifications of nervous system, renal organs 

 (nephridia), and general form o£ body seen in the other Mol- 

 lusca. Especially valuable in this respect is the memoir of Dr. 

 Spengel (Zeitsch. wiss. Zoologie, vol. xxxv.), entitled " The Olfac- 

 tory Organs and the Nervous System of the Mollusca. — A Con- 

 tribution towards the recognition of the Unity of the Molluscan 

 Type." The gradual loss of bilateral symmetry in the Grastropod 

 Molluscs, and the morphological consequences of torsion of the 

 region of the body covered in these animals by the shell (which 

 no doubt has been the cause of such torsion) are explained and 

 enforced by means of new arguments based on new facts. 



The development of the Polyzoa, probably the most difficult 

 problem (uot excluding even that of the Mammalia) which em- 

 bryologists have yet attacked, has formed the subject of two 

 important memoirs by Dr. Jules Barrels, who, it is gratifying to 

 state, has recently been authorized by the French Government 

 to establish at Villa Franca, near Nice, a public zoological labo- 

 ratory, which will be open to the naturalists of all countries who 

 may wish to make use of it in the prosecution of their investi- 

 gations. 



Crustacea. — Apart from the important work (always progress- 

 ing) of the identification of new species and genera in this group, 

 the investigations of Dr. Delage, a pupil of M. de Lacaze Duthiers, 

 on the circulatory ajjparatus of the Edriophthalma deserve special 

 notice. A remarkable supra-neural artery similar to that of the 

 Scorpions and Limulus has been discovered in these forms by 

 M. Delage by means of careful injections (Archives de Zoologie 

 experimentale, 1881). The observations of Mr. Conrad Beck 

 (Ann. & Mag. Nat. Hist. 1881) on new Cladocera from the English 

 lakes show how much interesting material there still exists under 

 the hands of English naturalists who may choose to explore 

 localities as yet but little studied ; whilst Prof. Lankester's 

 studies on Ajjus cancriformis (Quart. Journ. Micros. Sci., April 

 1881) show that even a well-known form may furnish new facts 

 of importance to careful observation. 



Aeachnida. — The latter naturalist has recently raised the 

 question of the affinities of the Kiug-Crab ; and has endeavoured, 

 by a cai'elul comparison of the external and internal structure of 

 this animal with that of the Scorpion, to show that the true posi- 

 tion of Limulus is, as maintained fifty years ago by Straus-Durck- 



