Miscellaneous. 539 



15. Sycandra HamholcUii, Hack. 



One specimen agreeing in skeletal structure with this species, but 

 its peristome is much produced. 



Loc. Mahou ; previously known fiom the Adriatic. — Sltzitnjsb. 

 Naturf.-Oesellscli. bd der Univ. Dorpat, Band vii. pp. 336-3il. 



0)1 a new Ehizopod, Arcyothris Balbianii. By M. Paul Hallez. 



In his culture of the ova oi Ascaris megalocephala Prof. Paul Hallez 

 discovered a very curious Rhizopod, to which he has given the name 

 of Arcyothrix Balbianii. It measures from 20 to 65 n accordin>i- 

 as it is more or less extended. Its irregularly globular body has 

 its lower surface flattened into a pedal disk, and the form of the 

 animal when creeping resembles that of a jockey-cap. Its proto- 

 plasm is transparent and contains, besides granules and vacuoles, a 

 large contractile vesicle, which M. Hallez found to communicate 

 with the exterior. He was unable to ascertain whether the animal 

 had a nucleus, as the employment of colouring agents would have 

 killed the ova under observation. This Ehizopod presents appen- 

 dages of two kinds, namely (1) a digitiform contractile pseudopo- 

 dium presenting slow movements of oscillation and rotation, and 

 (2) two very long and slender filaments of varicose aspect and often 

 bifid, which serve to retain what the pseudopodium has seized. 

 They are inserted upon two mamilloe, which are pretty close to- 

 gether, and in contracting they may form a spiral resembling that 

 of the peduncle of the Vorticellce*. 



These appendages play no part in the locomotion of the animal, 

 which is a simple reptation of the protoplasmic mass. Although 

 M. Hallez has only once met with this Protozoou and could not study 

 its development, his discovery of it is of considerable importance. 

 The simultaneous presence of the pseudopodium of the Amoebans 

 and of the filaments of the Heliozoa leads to the supposition that 

 Arcyotlirix Balbianii may be regarded as a type intermediate be- 

 tween these two groups. (The outline figure given of the animal 

 (a side view) shows a depressed irregular cone having the flat 

 creeping surface below and the single pseudopodium springing from 

 the apes. Two long slender threads, thickened at intervals, spring 

 from two conical projections on one side of the cone, and a flagel- 

 late Infusorian is shown as retained by one of these filaments. 

 The contractile vesicle is placed immediately beneath the base of the 

 lower of the two filaments.) — Memoires de la Socieie des Sciences de 

 Lille, ser. 4, tome xiv. ; Ball. Scient. da Dep. du Nord, October 

 1885, p. 323. 



* Podostoma Jiliyerum, according to Claparede, can retract the fila- 

 ments which it emits in the same way. 



