72 Records of the Indian Museum. [Vol. XV, 



is there an uninterrupted space, containing more or fewer of the cells 

 to be described ; this space, as has been mentioned above, opens into the 

 cavity of the sheath round the dorsal vessel. 



From the margins of this opening, i.e., from what may be called the 

 mouth of the gland, a number of muscular fibres take origin, as has been 

 described by Schneider ; these pass into the gland, and then branch 

 and radiate ; they are perfectly distinct from the reticulum. 



Within the gland are contained numerous cells, of irregular shape, 

 with rounded nucleus containing a pseudonucleolus ; their processes 

 may resemble pseudopodia, and the nucleus may be excentric. These 

 are leucocytes, and as their characters are well known, they need not be 

 further described. 



These cells are more compactly aggregated at the periphery of the 

 gland, where they form fairly solid masses corresponding to the lobula- 

 tions seen on the surface ; each such lobule is surrounded by a corre- 

 sponding outward bulging of the enveloping membrane or capsule. The 

 cells are also contained in the meshes of the reticulum of the gland, 

 but are here more loosely aggregated ; in the centre of the gland towards 

 the opening into the sheath of the dorsal vessel they are still more 

 scattered. 



The cells are to be looked on as proliferated from the inner surface 

 of the capsule within the peripheral lobulations ; thence they travel 

 into the central part of the gland, and ultimately they reach the general 

 body-cavity through the sheath around the dorsal vessel, which, as 

 already explained, communicates with the cavity of the next posterior 

 segment. 



From what has been said, it will be seen that I regard the capsule 

 as peritoneal in origin ; it is indeed, as fig. 3 shows, continuous with the 

 septum, and may be looked on as in fact an irregular sac-like forward 

 bulging of the septum, which has become extremely thin by the loss of 

 all muscular elements, — which has been indeed reduced to a thin sheet 

 of peritoneal cells only. No doubt this sheet is morphologically double, 

 and results from the coalescence of the two layers of peritoneum cover- 

 ing the two faces of the septum, but its double character is not to be 

 made out in the actual specimens. 



I differ, therefore, from both Beddard and Schneider in the concep- 

 tion of the essential nature of these organs ; neither author seems to 

 have recognised the capsule, or bulging of the septum within which the 

 cells are contained. Beddard's idea is that the organ is a mass of cells 

 surrounding a few muscular fibres ; while Schneider speaks of a definite 

 opening in the sheath of the dorsal vessel, through which the cavity of 

 one segment communicates with that of the next adjacent, and the 

 gland is a tree-like branching structure originating from the margins 

 of the opening. 



I must guard myself from saying that the capsule is to be made out 

 as a complete investment over the whole periphery of the gland in every 

 section ; it seldom is so, in this species at any rate. At places the cells 

 of the gland are closely adherent, so that the capsule does not stand off 

 as a separate structure, and frequently the capsule is absolutely conti- 

 nuous with the cells. This of course necessarily follows from the 



