lgo8.] J. Stephenson: The Anatomy of some Aquatic OUgochœta. 267 



made out. They vary in number from two to four on each side; one specimen, 

 however, appeared to have one only on one side; the two sides have not always the 

 same number ; there may be four on one side and two on the other. They are 

 attached to the oesophagus by strands of tissue which are probably ducts, often also 

 to the body- wall and to each other. They are present in the fourth and fifth segments, 

 sometimes also in the third, or sixth, or in both third and sixth. The duct of the 

 gland in the sixth segment usually runs transversely to the oesophagus, while the 

 ducts of the glands of the fourth and fifth segments take a more forward course ; that 

 of the gland of the fourth segment may reach the hinder end of the pharynx, or may 

 enter the oesophagus in the third segment; when glands are present in the third 

 segment, their ducts enter the hinder end of the pharynx (figs. 25, 29). 



In general, the glands are somewhat lobed, of hyaline appearance, and may have 

 some resemblance to an ovary. Their size, like their distribution, is variable. 



Beddard [i] describes the septal glands as masses of pear-shaped cells, each cell 

 being prolonged to form its own duct, and the ducts appearing to enter the pharynx. 

 He thinks they are simply epidermic glands which have been invaginated along with 

 the stomodseum. 



I have not been able to see the actual prolongation of each cell into a separate 

 duct ; and the ducts seem in the majority of cases to enter the oesophagus and not 

 the pharynx. Instead of saying that they are epidermic glands which have become 

 invaginated, I should prefer to describe them as pharyngeal digestive cells which have 

 lost their direct connection with the alimentary canal. My meaning will be clear on 

 comparing the diagrams of the pharynx of Nais variabilis, plates xv, xvi, figs. 2, 14, 

 with figs. 29 and 38, plate xviii. The pharynx of Nais occupies the third, fourth 

 and fifth segments, and has a nodular appearance due to its being surrounded by a 

 number of ovoid or pear-shaped hyaline cells ; it will be at once apparent that the 

 pharynx of Nais is the equivalent of the pharynx plus most of the oesophagus of 

 Pristina ; that this part of the oesophagus of Pristina is simply the pharynx of Nais 

 stripped of its cells, which are here aggregated to form septal glands ; and that the 

 variable length of the pharynx of Pristina {v. sup.) simply depends on the amount 

 of this ''stripping" that has taken place. The variations in size, distribution and 

 ducts of the septal glands are thus easier to account for; and it would seem that 

 the ''pharynx" of these animals is not so much a muscular organ as a glandular 

 one. 



The stomach (glandular ventricle of Beddard) is a small globular saccule in the 

 eighth segment (fig. 25). The glandular appearance of its walls is due to large ovoid 

 or tailed nucleated cells, and the longitudinal markings which may be faintly seen are 

 the intervals between these cells. The walls of the stomach contain also a number 

 of brown particles resembling minute droplets of oil. The intestine also contains in 

 its wall these coloured particles, which may, however, be absent from the posterior 

 fourth of the body; an " antiperistaltic" action is usually to be observed, as in Nais', 

 and the large cilia of this part of the tract work, as also in Nais, in a direction from 

 behind forwards. 



