British Orihatidw. By A. D. Michael. 233 



as Duges describes a partial dissolution, although he thinks that 

 the legs, for instance, are formed at the expense of the old legs 

 instead of from the general mass of the body, which Megnin 

 denies, and which does not coincide with my own opinion. 



As a rule, the integument of the larva and nymph of the 

 Orihatidm is soft and light-coloured ; in the perfect creature it is 

 hard and dark ; this is subject to the modification hereafter 

 mentioned. 



In the final change, which I have carefully watched in the case 

 of Tegeocranus latus and Oribata punctata, the adult nymph 

 gradually becomes inert, creeps into a hole or sheltered place, and 

 seems to me to fix its claws firmly in whatever it is resting on ; it 

 then becomes motionless and to all appearance dead. In one or 

 two instances with Tegeocranus latus I carefully cut out the minute 

 piece it was fixed on, and placed it where I could see it better, 

 preserving the same conditions ; in this state it remained for about 

 a fortnight without any signs of life, at the end of that time the 

 skin got rapidly darker, and about twelve hours after, the skin 

 split at the posterior edge (the creature being a flat oval) and the 

 anal margin of the body of the adult slowly appeared by the skin 

 shrinking from it ; this splitting along the edge and shrinking of 

 the skin imperceptibly proceeded from behind forward, the creature 

 remaining motionless. After five or six hours one could see that 

 the parts of the perfect creatiu-e were formed independently of the 

 similar parts of the nymph, the legs, for instance, not being formed 

 within the old legs which were stretched out, but being folded on 

 the body and secm*ely packed within the depressions between the 

 protecting ridges before mentioned. When the skin had split 

 sufficiently far, the perfect creature at last moved, slowly unfolded 

 its legs, withdrew its cephalothorax from the fore part of the old 

 skin, like a finger from a glove, and walked off, leaving the old skin 

 with outstretched legs in the same position it had occupied for a 

 fortnight. 



With regard to the discovery of the nymph of Tegeocranus 

 latus, one day, when searching for Oribatidse amongst moss on an 

 old tree stump in Epping Forest, I found between the moss and the 

 wood a creature new to me. On examining it under the Microscope, 

 I found that it belonged to the family I wanted, but was so strange 

 and bizarre that I hardly knew how to class it ; it was a flat oval, 

 the edge cut into great triple serrations difficult to describe, and from 

 each serration sprang a long thick spine, bent into an elegant 

 double curve and armed with short thorns, while ring within ring 

 on the back were the cast dorsal skins of the earlier stages, each 

 bearing its own serrations and spines, so that the whole dorsal 

 surface was a chevaux-de-frise, the ventral surface being pressed 

 close to the wood. At once there arose the question, was this 



