574 FRANK B. BEDDARD. 



more or less regular fashion along both sides of those cells. 

 The typhlosole is a simple fold. 



The integument in the youngest specimens at my disposal 

 was chiefly interesting on account of the structure of the 

 epidermis and of the longitudinal muscular coat. In the epider- 

 mis the gland-cells are limited to an area in the middle of each 

 segment ; it is evidently here that they first appear. In the 

 longitudinal muscular coat the fibres are embedded in the same 

 gelatinous material recognisable in mature worms, but this is 

 proportionately less in amount, and there is no thick layer of 

 it separating the longitudinal muscles from the peritoneum. 

 The fibres themselves approximate in their arrangement very 

 closely to Lumbricus; that is to say, they are disposed in 

 double columns, which are not, however, perfectly regular. 



The nephridia in these embryos presented features of con- 

 siderable interest. The paired nephridia were recognisable in 

 all the segments after, and including, the fourth ; the first pairs 

 are not covered with the coating of peritoneal cells containing 

 numerous spherules, as are the succeeding pairs. This invest- 

 ment of the nephridia commences gradually, inasmuch as those 

 of the fifth pair had only a very slightly developed peritoneal 

 layer, in which, however, the granules of secretion, which stain 

 deeply, were perfectly plain. 



The anterior pairs of nephridia are, as also in the adult worm, 

 closely attached to the posterior wall of their segment. They 

 are not bound thereto by any mesentery, but lie in actual 

 contact with the septum. The duct leading to the exterior 

 passes down, in the case of the anterior nephridia at any rate, 

 also in close contact with the septum ; it is much coiled, and 

 so in longitudinal sections appeared, in every section, cut at 

 right angles to its course. Arrived near to the insertion of the 

 septum on to the body-wall the duct joined a continuous 

 longitudinal duct, passing along the first few seg- 

 ments of the body and putting the nephridia of these 

 segments into communication with each other. On 

 each side of the nerve-cord this duct was found having similar 

 relations to the nephridia of the segments through which 



