THE ANNALS 



MAGAZINE OF NATUEAL HISTOEY. 



[FIFTH SERIES.] 



No. 93. SEPTEMBER 1885. 



XVII. — On Phoenicurus. 

 By M. H. DE Lacaze-Duthiers *. 



While investigating Tethys leporina in the spring, at the 

 Laboratoire Arago, I found in large quantities the curious 

 parasite which that moUusk bears attached to its sides. 



Upon Phmnicurus, which is the name of the parasite, we 

 have only very imperfect information ; but it was known to 

 Rudolphi, Cuvier, and Delle Chiaje. This last naturalist, 

 who at first thought he was the discoverer of it and called it 

 Planariay indicated how it is attached by its mouth to the 

 mamillge which are observed in the middle of the inter- 

 branchial foss« of the Tethys ; he recognized in the interior 

 of its body the numerous muscular bands which give it great 

 contractility, as also the chief part of its digestive tube ; but 

 although he has given some good figures of the exterior of 

 the animal his indications of its organization, when given, are 

 very unsatisfactory. 



A favourable opportunity having presented itself, the fol- 

 lowing are some of the facts which I have ascertained : — 



The body of Phcenicurus has the form of a boy's kite ; it 



* Translated from the ' Oomptes Rendus de rAc.ad6mie des Sciences, 

 July 6, 1885, tome ci. pp. 30-35. 



Ann. & Mag. N. Hist. Ser. 5. Vol. xvi. 12 



