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DESCRIPTION OF A NEW SPECIES OF ARIUNCULUS 

 FROM ALGERIA. 



By WALTER E. COLLINGE, M. Sc, 

 The University, Birmingham. 



Some short time ngo I received from Mr. P. Pallary a number of live 

 specimens of Algerian slugs, amongst which was the specimen forming the 

 subject of this paper. Unfortunately there was only a single specimen, but 

 Mr. Pallary has very kindly promised to try and procure more, in order that 

 a more detailed account may be given of the generative organs and a coloured 

 figure of the animal. 



I have much pleasure in associating the name of Mr. Pallary with this 

 interesting species. 



Ariunoulus pallapyi, n. sp. 



Animal (alive) reddish-brown, darker medio-dorsally, with three faint, 

 ill-defined, blackish lines running from the posterior border of the mantle to 

 the tail, where they converge ; mantle smooth, light brown, with faint red- 

 dish tinge, which latter quickly disappears on placing in alcohol ; head and 

 tentacles yellowish-brown, darker dorsally. Rugae elongated, flat, clearly 

 marked by definite sulci. Caudal gland well defined, but partially hidden 

 by the margin of the foot. Respiratory orifice situated towards the anterior 

 end of the mantle. Generative orifice about half way between the right 

 upper tentacle and the respiratory orifice. Peripodial groove sharply marked. 

 Foot-fringe and foot-sole lighter in colour, latter divided into median and 

 lateral planes. 



Length (alive) 72 millim. ; (in alcohol) 50. 



Shell a thick, somewhat pyriform calcareous plate. 



Maj. diam. 6.2 millim., min. 4. 



Hah. — Echmiihl, Oran, Algeria (P. Pallary). 



This, the largest known species of Arhmculu-s, at first sight gives one 

 the impression of an elongated form of Avion suhfuscus, Drap. Anatom- 

 ically it is very distinct from any of the described species. 



The vestibule of the generative organs leads into an elongated vagina, 

 which suddenly widens out to form a large globular sac, with a somewhat 

 complicated internal structure. From the posterior and outer border of this 

 sac the receptacular duct is given off, while ventrally and slightly anteriorly 

 is a large retractor muscle. On the same side at the anterior end is the 

 free-oviduct, and at the opposite side and posteriorly the sperm-sac arises. 



The remaining organs have not yet been examined in any detail. 



