TIIK A.V.N A LS 



M.\a.\Z[.\E OF .\'.\T[JR.\L insTORY. 



[SEVENTH SERIES.] 

 No. 26. FEBRUARY 1900. 



XVIir. — On the Nephridium of Nephthjs caeca, Fahr. By 

 Francis Hugh Stkwakt, M.A., Gatty Marine Laboratory^, 

 St. Andrews. 



[Plates n. & III.] 



During the summer of 1899, while working at tlie Gatty 

 Marine Laboratory, St. Andrews, it was suggestei to me by 

 Professor M'Intosh tliat, in view of the wonderful supply of 

 living material obtainable in St. Andrew.-* Bay, it might be 

 profitable to continue the work of Mr. Edwin Goodrich on 

 the nephridium of Xephthys (Q. J. M. S. no. 157). In so 

 doing I have been able to confirm Mr. Goodrich's results 

 in all points except one — the position of the organ relative 

 to the blood-vessel.^. This, as described and figured by him 

 is briefly as follows : — The ciliated organ lies in the angle 

 between the dorso- ventral vessel and the branch x (PI. II. 

 fig. 1) ; the nephridial tube passes down the dorso- ventral and 

 along the branch y, the solenocyte-bearing tuft resting in 

 the angle between the dorso-lateral and the branch x. 



After a most careful e.Kamination of the subject, I have 

 come to a different conclusion. The ciliated organ rests not 

 between the dorso-ventral and j: (PI. II. fig. 1), but at the 

 junction of the ventro-lateral, the dorso-ventral, and y; the 

 solenocyte-bearing tuft lies in the angle between the vetjtro- 

 lateral and the dorso-ventral, not between the dorso-lateral 



Ann. 1- }f<tj. .V. flht. <,rv. 7. Vol. r. 11 



