632 MK FRANK E. BEDDARD ON THE 



second segment, and are disposed in four longitudinal rows ; but there are invariably two 

 closely approximated setae in both the dorsal and ventral rows. The second seta does not 

 in any way suggest the idea of its being a " reserve seta ;" indeed, in several cases 

 " reserve setae," more or less immature, and to the number of two, were present in addition 

 to the fully formed and functional setae. 



The setae are implanted so as to divide the circumference of the body into four areas ; 

 the distance, however, between the ventral pairs is less than that between the dorsal and 

 ventral pair of one side, and the distance between the two dorsal pairs. In fact, the 

 diagrammatic transverse section illustrating my previous note upon this worm [A 1, pi. 

 xxiii. fig. 7], proves to be not quite correct when checked by my subsequent observations 

 upon other examples. The arrangement of the setae, therefore, in Phreoryctes Smithii 

 brings the genus nearer to the Lumbriculidae, when there are four rows of pairs of setae. 



Another point in which Phreoryctes Smithii differs from the other species of the 

 genus is in the shape of the setae. 



In both the other species the shaft, the portion implanted in the body-wall, is 

 straight; this is shown in the figures, e.g., of Timm and Claparede and Vejdovsky. 

 In Phreoryctes Smithii this is not the case ; the setae are bent throughout, and have the 

 shape so characteristic of the setae of the Oligochaeta (vide Plate, fig. 6). 



In their shape, therefore, as well as in their number and arrangement, the setae of 

 Phreoryctes Smithii are much more like those of the Lumbriculidae than are the setae of 

 Phreoryctes Menkeanus and Phreoryctes filiformis. On the other hand, the present 

 species agrees with the others in the fact that the dorsal setae are much larger than the 

 ventral. Fig. 6 is drawn with the aid of the camera lucida, and therefore illustrates 

 accurately the relative sizes of the dorsal and ventral setae. This difference is not, 

 however, obvious on the anterior segments of the body. 



Absence of Genital and Penial Seta. — It is important to put on record the fact, that 

 in the neighbourhood of the reproductive apertures there is no modification whatever 

 of the setae. It is not possible to state with absolute certainty that Phreoryctes has no 

 genital setae, but it is at least highly probable that this is the case. This again is a 

 point which bears upon the affinities of the genus. Most Oligochaeta show some modifica- 

 tion of the setae on the genital segments, but this is apparently not so with, e.g., the 

 Lumbriculidae, which family Phreoryctes, as has been already pointed out, resembles in 

 other particulars. 



Body -Wall. 



Phreoryctes Smithii does not differ from the other species of the genus in the 

 structure of the body-wall ; I have, therefore, but little to say under this head. 



The epidermis (see fig. 12) is like that of Lumbricus and many other Oligochaeta 

 in the specialisation of its cells into large glandular cells and narrow interstitial packing 

 cells. 



The relative thickness of the two muscular layers is shown in fig. 12. 



