404 NOTES AND MEMORANDA. 



whereas that of the liver converts it into glucose, and, in an acid 

 solution, digests fibrin ; this latter organ contains no traces of bile 

 acids or pigments, and yet M. Fredericq is unwilling to propose any 

 alteration in its name. 



Nervous and Muscular Systems. — M. Fredericq is of opinion that 

 the supra-oesophageal ganglia are the seat of psychical processes and 

 ought to be compared to the cerebral hemisphere of the Vertebrata ; 

 he states that the sub-oesophageal masses contain the centres for the 

 resj)iratory movements, the chromatic function, and for the movements 

 of the various muscles of the body ; he comes to the same conclusion 

 as Colesanti as to the physiological similarity of a single arm and a 

 decapitated frog ; there are in it no true volxmtary movements, but the 

 reflex ones are manifested much more energetically. 



In chemical composition the muscles seem to resemble those of 

 the Vertebrata ; the aqueous extract contains an enormous quantity of 

 taurine, and the so-called idio-muscular contraction can be very easily 

 caused to appear in the muscles of the mantle. 



Neomenia and the other Amphineura. — Dr. Jhering gives * 

 an abstract of the work lately done on this subject, and does good 

 service in iJointing out that the name Solenojms Sars was published 

 without any description, and that therefore it cannot take the place of 

 Tullberg's name — Neomenia. The heart is found to have a similar 

 position — median and dorsal — to that of the same organ in Chiton, 

 but the view that Neomenia is hermaphrodite does not find acceptance 

 with Jhering. The observations of Graff on the nervous system 

 appear to point to the natural character of the group Amphineura, in 

 the opinion of its founder, who takes occasion to point out that 

 Mr. Ball's palasontological researches confirm his views of the phylo- 

 genetic relations of the Patellidce with the Tecturidce. It may be of 

 interest to note that Keren states that he has known this remarkable 

 Neomenia for the last thirty years. 



Anatomy of Chiton. — H. von Jhering describes f the results of his 

 own observations on some points in the structure of these eminently 

 interesting Mollusca, and gives a critical revision of the statements of 

 previous authorities. Looked at from his point of view, as, indeed, 

 from any, the importance of these forms cannot be overestimated ; 

 our author regards the Chitons as intermediate between the Mollusca 

 proper and the Annelides, and is of opinion that their developmental 

 history is much more similar to that of the just-mentioned Vermes than 

 to that of the Gasteropoda. It is, indeed, only of late years that these 

 forms have foimd theu* proper place in the zoological system ; Latreille, 

 in 1820, placed them with the Trilohites, and de Blainville, in 1825, 

 with the Cirripedia. The observation of Herr Jhering was chiefly 

 turned to the generative and renal organs and the histological charac- 

 ters of the muscular system, dm-ing his late stay at the Zoological 

 Station at Trieste ; these are his conclusions : — 



1. The Chitonidfe are dioecious. 



2. The ovarian eggs are enclosed in a follicle; in C sqiiamosus 

 this secretes a spiny chorion. 



* ' Morphol. Jahrbucli,' iv. (1878) 147. t Ibid. 128. 



