

Miscellaneous. 391 



large cilia. And here even the fleece of fine cilia which the last- 

 named author found in the Autoh/ti, and which may be of some use 

 to them as the larvae are free in the maternal sac, is not developed, 

 the movements of the mother rendering the presence of a locomotive 

 apparatus in the young animal of no use. 



I have gone into some details upon this type because it is the one 

 that has served as the foundation of the theory of lateral buds. Such 

 an exception to the general rule, according to which buds are produced 

 in the longitudinal direction in free animals, would have been very 

 difficult to interpret ; and it was received with much reserve. M. 

 Mecznikow will not decide upon it ; Clapaivde declared it to be 

 improbable ; and I only find M. Vaillant who accepts it without 

 hesitation, and cites it in support of another still more singular notion 

 which does not seem to have had a better fate. I do not think, 

 however, that any one has combatted M. Pagensteeher's theory by 

 the actual investigation of his type ; but for this I cannot answer 

 in the present state of the University library of Algiers, and it is 

 a point which I shall look to in the memoir which I propose to de- 

 vote to this annelid and other allied types. I have not, in fact, con- 

 fined myself to the investigation of E. gemmifera ; and I have been 

 able to reexamine all the types spoken of by the German author. 

 In. his L\ Martinsi particularly, which II. Ehlers regards as a true 

 Sr/llis, and which is undoubtedly the Splice rosyll is pirifera of Clapa- 

 rede, I have met with males and females of the two forms, with and 

 without long setse. 



This E. Martiasi cannot be separated from E. gemmifera, and, 

 like it, shows the absence of the dorsal cirrus on the second para- 

 podium. If it is really the Sphcerosyllis of Claparede, this character 

 escaped the notice of the Genevan naturalist. It would thus be 

 probable that E. gemmifera would enter into his genus Pcedophylax. 



Comptes Rendus, March 12, 1883, p. 728. 



On the Parasites of Anodouta tluviatilis. 



Prof. Leidy directed attention to a basketful of living freshwater 

 mussels, Anodonta fluviatilis. 



The mussels are infested by many water-mites creeping about 

 among the gills. The young of the same, in various stages, were 

 observed imbedded in the mantle. The mite appears to be identical 

 with the species Atax ypsilophorus, which is a parasite of the common 

 freshwater mussel (Anodonta cygnea) of Europe. It was discovered 

 and described j ust 1 < K) years ago under the name of Acarus ypsilopho- 

 rushy Dr. Christophori Gottlieb Bonz (Nova Afcta Phys. Med. Acad. 

 CL.C. Nat. Cur., Nuremberg, 1783, p. 52, tab. i. figs. 1-4). It is 

 described and figured by Pfeiffer with the name of Limnochares ano- 

 donta (Naturg. deutscher Land und Susswasser-Mollusken, 1821, 

 Taf. i. fig. 12), by Dr. Karl Ernst v. Baer under the name of 

 Hydrachne concharum (Nova Acta, Bonn, 1826, p. 590, Taf. xxix. 

 fig. 19), by P. J. van Beneden (Mem. de l'Acad. E. des Sciences de 



