TUBIFEX. 307 



earlier observers, but there are several inaccuracies, most 

 of which have been noticed and corrected by still more 

 recent observers. Many of the terms then in common use 

 have since been discarded, and to some of these Beddard 

 in his Monograph of the Oligochaeta refers, viz., the 

 capsulogenous gland is now known as the spermatheca, 

 the cloaca as the spermiducal gland, the vesicula seminalis 

 as the sperm sac and the matrice as the egg sac. 



In 1871 Mcintosh published a paper in which 

 he gives short accounts of certain of the organs, but no 

 complete description of any system except the circulatory, 

 as he concentrated attention on certain minor points such 

 as the perivisceral fluid and corpuscles and the granular 

 glands which form a complete investment around the 

 intestine and dorsal vessel. His results will be considered 

 in detail later. 



Vejdovsky in 1884 published his well-known work 

 " System und Morphologie der Oligochaeten." In this he 

 makes frequent reference to Tubifex, and increases a good 

 deal our knowledge of the structure of this worm. But in 

 a work which embraces the whole of a large group it is 

 impossible to describe in any great detail the structure of 

 one member of that group. The same may be said of 

 Beddard's Monograph of the Oligochaeta, published in 

 1895. 



Several other papers have been inserted in the 

 Bibliography at the end of this work. Some of these deal 

 only with one small part of the subject, and reference will 

 be made to them in the right places. Others have been 

 mentioned in the list because they have some more distant 

 bearing on the work, but yet are sufficiently allied to it 

 to be of interest. 



It has seemed advisable to revise all this scattered 

 work, and, by a careful and detailed investigation of the 



