198 Mt'sceUaneoiif^. 



sions into the buccal membrane or the test, if these are made in the 

 intervals between the courses of the nerves, and even after the 

 removal of a considerable portion of the upper hemisphere of the 

 test, contaiiiini* the anus, a portion of the intestine and genital 

 glands, the terminal nerve-cords and ambulacral vessels. All these 

 results lead to the conviction that the cords dcscrilied as forming 

 the nervous system are the means by which harmony of movement 

 is produced. Lastly the galvanization of an ambulacral nerve by 

 means of the electrical forceps and induction-coil constantly causes 

 the immediate retraction of all the ambulacral feet of the zone. 



The following facts seem to be in favour of the existence of a 

 nervous plexus in the skin w^hich covers the outside of the test. If 

 a certain spot in this integument be wounded or pricked, the spines 

 and pedicellarite within a certain radius immediately lower them- 

 selves towards the point irritated, evidently for the purpose, of 

 defence. This experiment succeeds equally well with fragments 

 entirely detached from the animal. It is in the thickness of the 

 external skin that the means of communication between the irri- 

 tated point and the muscles moving the spines and pedicellariae are 

 situated ; for by cutting the integument with a fine scalpel, the 

 space that takes part in the above defensive movements may be 

 limited. The author, however, has apparently been unsuccessful in 

 his search for this assumed nervous plexus. — Comptes Rendus, Nov. 

 13, 1876, p. 908. 



On the Motile State of Podophrya fixa. By M. E. Maupas. 



Claparede and Lachmann were the first to recognize the real 

 organization of the Acinetiua, for which they created the order of 

 Infusoria Suctoria. These authors regarded them as essentially fixed 

 organisms ; and the Acinetina thus became isolated among their re- 

 latives. 



The observations of the above-named naturalists upon the ciliated 

 embryos of these Infusoria, with those of Stein, Cienkowski, and 

 others, showed, however, that this isolation was not so profound as 

 had been supposed at first : during their youth the Acinetiua are 

 motile and furnished with vibratHe cilia. 



The author's observations, which he regards as fitted to bring to- 

 gether more closely the iSuctoria and Ciliata, were made upon Podo- 

 phrya fixa, Ehr., which can at pleasure pass from the motile to the 

 fixed state. They were made in November 1875 and October 1876 

 upon Podophryoe obtained from the rivulets of Frais-Vallon near 

 Algiers. 



Whether free or fixed, the body of Podophrya fi^va is always more 

 or less globular, sometimes quite spherical. The suckers are distri- 

 buted pretty regularly over the whole body, except only a small 

 region of the periphery, always corresponding to the part of (he body 

 where the contractile vacuole is situated. 



After observing some of these Podophrycn for from half an hour to 

 an hour, the author saw the suckers slowly drawn into the body ; and 



