572 BRITISH ORIBATID^. 



tlie femora are sculptured, almost reticulated. The 

 claws are mo7iodactyle, but there is a minute projection 

 at each side of the claw, and two longish, fine hairs, 

 sharply hooked at their distal ends, on each side of 

 each claw ; other hairs on the legs chiefly very short, 

 slightly thickened, or spike-like, some ; when seen by 

 a high amplification, of almost laurel-blade form, and 

 somewhat dark in colour. Tactile hairs and some of 

 those on the tarsi fine as usual. 



Abdomen almost elliptical, slightly narrowed ante- 

 riorly, or it may be called more oval; only slightly 

 arched, the edges being sharply deflexed. Where 

 this bending downward commences, on each side, is a 

 slight, ill-defined ridge ; or, in some specimens, only a 

 sudden, slight sinking of the margin. On the anterior 

 narrowed part of the abdomen are usually three or 

 four more or less transverse, broad, irregular ridges ; 

 from immediately behind these, in most specimens, 

 two rather broad longitudinal ridges run backward 

 until a short distance from the hind margin ; these two 

 ridges enclose a central parallelogram not quite a third 

 of the width of the whole notogaster. It is from these 

 ridges that the species is named ; they are not, how- 

 ever, usually regular single ridges, but are broken up 

 into two or more lengths, which often overlap, or 

 spring one from the other. In some specimens they are 

 almost or entirely absent, when the creature looks 

 very like S. maculatus. Behind the longitudinal ridges, 

 and often joined to their posterior ends, are two or 

 three transverse ridges, mostly having a bend forward 

 about the middle, but the whole of the markings are 

 irregular and subject to considerable variation. The 

 whole notogaster is strewn with dots similar to those 

 on the cephalothorax, but perhaps a little larger ; these 

 dots average about eighty to the millimetre ; they give 

 the abdomen a very broken outline. Ventral surface 

 rough with irregular, ill-marked ridges and depressions. 

 Grenital and anal plates large, near together ; the former 

 very square, the latter pentagonal and elongated. 



