400 BIMTISH OEIBATID^. 



stagnant, and which contains growing water- weeds. 

 It is interesting from the condition of the pseudo- 

 stigmata and pseudo-stigmatic organs. 



Colour dull reddish-brown, it is, however, generally 

 more or less covered with a whitish, somewhat iridescent 

 deposit, which is most commonly found in irregular 

 strips and patches round the periphery of the abdomen. 

 The creature is also occasionally found coated with 

 diatoms, which adhere tightly to it. 



Texture smooth but not polished. In dissections of 

 favorable specimens it may be seen that the notogaster 

 is finely punctured, punctures about 140 to the milli- 

 metre, distance between the punctures about three 

 times the width of the punctures. 



Cephalothorax less than half the length of the abdo- 

 men, almost conical, nearly as wide at its base as the 

 progaster. Rostrum blunt-pointed ; the point, which is 

 rounded, is divided from the side of the rostrum by a 

 slight notch ; there is a thickened plate on the anterior 

 part of the f rons bearing the rostral hairs, which are 

 short and curved. Mandibles short, very stout and 

 strong, movable arm of the cheta the longest and 

 quadridentate. Maxillse remarkably strong, deeply 

 dentate, and divided into two bifid lobes. Palpi with 

 terminal joint thickened and slightly bifid at the distal 

 end, the inner division being prolonged to a blunt 

 point. No true lamellsB nor translamella, but there 

 are two pairs of rather irregular ridges, one of which 

 probably represents the lamellae. The inner pair of 

 these ridges are less than half the length of the cephalo- 

 thorax, the outer, which are less constant, are at least 

 three-quarters of its length ; both spring from the base 

 of the cephalothorax, where the two ridges of each 

 pair are furthest apart, approaching more closely at 

 their distal ends. As the creature is usually found 

 neither the pseudo-stigmata nor the pseudo-stigmatic 

 organs project at all from the cephalothorax; the 

 former are exceedingly minute roundish holes, near 

 the base of the cephalothorax, leading into short, some- 



