230 G. M. Giles -Notes on the Arnpliipoda of Indian Waters. [No. 3, 



blastic layer is so thin as to be scarcely perceptible. It is a simple 

 rounded channel without foldings or complications of any sort. The 

 large size of the canal is no doubt connected with the bulky nature 

 of the food in proportion to its contained nutriment. Tn all but one 

 of the sjDecimens cut the intestinal canal was full and its contents 

 simply mud, exactly similar to that clinging to the outside of the 

 animal, which appears to live by swallowing the mud without any parti- 

 cular selection, trusting to the elaborate arrangements of its digestive 

 apparatus to separate and utilize any particles that may possess a nutri- 

 tive value. 



Glatiditlar System. — This in our species possesses but a feeble deve- 

 lopment. Situated below the main mass of the supra- oesophageal ganglion 

 is the green gland, consisting of a mass of somewhat elongated cells en- 

 closed in a distinct capsule. The situation of its duct could not be made 

 out. The liver lies behind the gizzard and immediately underneath the 

 anterior end of the dorsal vessel. It is of small size, and does not com- 

 pletely sheath the mid-gut, being placed almost entirely above and at 

 the sides. Certain glandular cells can also be made out within the 

 basipodites of certain of the thoracic appendages, notably of the fifth, 

 but the position of their ducts could not be discovered with certainty, 

 although I am inclined to think that the opening is in the propodite, 

 near its articulation with the dactylopodite. 



Vascular System. — The dorsal vessel is a tube of considerable size 

 occupying the greater part of the space between the great extensor 

 muscles of the segments above and the intestinal canal below ; and is 

 slightly constricted at the points of junction of segments. Of large 

 size in the thoracic region, it tapers off, in front and behind, and 

 is lost. Beyond the constrictions, already mentioned, no signs of valves 

 could be made out. It appears to open by minute, oblique slits into the 

 general lymph spaces surrounding it. In histological structure it con- 

 sists of an inner layer of flat, polygonal epithelioid cells, covered by a 

 layer of flattened nucleated fibres disposed in a regular spiral round the 

 tube, the ostioles communicating with the lymph space consisting of 

 interstices between the thus obliquely placed fibres (PL II, Fig. 3). 

 The general body cavity is divided into lateral halves by a delicate 

 vertical septum connecting the dorsal vessel with the body wall above 

 and witb the intestinal canal below, and each half is further subdivided 

 by a horizontal septum running from pleuron to pleuron above the genera- 

 tive gland tubes to the side of the intestine. 



Organs of Respiration. — The branchiae of our species attain an ex- 

 ceptional degree of complexity. There are five pairs, which are at- 

 tached to the coxopodite of each of the thoracic appendages except the 



