A. D. MICHAEL ON TWO SPECIES OF ACARINA. 117 



In the first pair it appears to have coalesced with the tarsus (unless, 

 indeed, the projection hereinafter mentioned be the homologue of 

 the tarsus), and together they form a great club-like mass which is 

 the leading characteristic of the creature, and which is larger than 

 the whole rostrum, and looks utterly out of proportion to the animal, 

 giving it a most comical appearance when walking. A little below 

 the centre of the anterior margin of this mass a great clear chitinous 

 blunt tooth projects straight forward. It has on the lower surface 

 an appearance of being articulated, and may possibly be the homo- 

 logue of the fifth joint ; but I do not think that this will turn out 

 to be so. It appears to me that the great single claw is articulated 

 not to the tooth, but to the mass before spoken of just where the 

 tooth springs, and that, therefore, the tooth would more probably be 

 the homologue of the absent second claw. The single claw which 

 terminates this leg is as disproportionately large as the tarsus which 

 carries it, somewhat bulbed near its insertion, the bulb striated with 

 curved ridges. From the bulb the claw turns almost at right angles, 

 and is curved, thick, bluntly-pointed and striated with oblique 

 ridges on the inner surface. There is not any sucker to this leg. 



The tarsi of the other legs are totally different, they are longer 

 than the third and fourth joints put together, elegantly tapered, and 

 terminated by a double claw set on a long peduncle; the claws stand 

 almost opposite to each other, and are short, stout, very sharply 

 curved, and have a sort of short inner claw with a pad or brush 

 under them in the second and third pairs of legs ; those of the 

 fourth pair are longer, slighter and of a more open curve, and lie 

 more against one another than the others ; the peduncle is straight 

 in the second and third pairs of legs and is continued below the 

 claws and terminated by a bell-shaped sucker. In the fourth pair 

 the peduncle is very long, the claws are terminal, and there is not 

 any sucker. 



The skeletal strengthening of the sternal surface appears to be as 

 follows : A central chitinous external ridge runs from the 

 caraerostomium to the hind margin of the cephalothorax, and sends a 

 branch partly round the camerostomium. Almost immediately 

 behind the cox^ of the first pair of legs a strong chitinous band 

 starts from the sternal ridge, and passes entirely round the creature 

 inside the dermal skeleton ; this is conspicuous, both from- the 

 dorsal and sternal aspects, in consequence of the transparency of the 

 chitine. Near the lateral margin of the body this ridge joins the 



