^64 MR. A. D, MICHAEL ON A NEW [Mar. 14 



are all in one piece and quite hard and stiff ; all the claws of 

 Herida are of this nature. The two hind pairs of legs of the 

 present species have tarsi and claws fairly similar to those of 

 Herida, except that the shaft is a little more bulbous ; the claws 

 are large, of the ordinary type, and spring from the ends of the tarsi. 

 The two front pairs of legs have an entirely different termination ; 

 the tarsi are very po^^•erful, strongly curved downward, particu- 

 larly at the distal end, and formed of stronger and denser chitin 

 than the rest of the legs ; they end in blunt points, and have the 

 appearance of the dactylopodite in some Crustaceans. They 

 form efficient climbing-organs, and the Acarus practically climbs 

 entirely by their aid. I watched it climbing some dozens of times ; 

 it got the curved ends of its tarsi on to or over the edges of small 

 pieces of stone or weed, and clinging to these slowly dragged itself 

 up. From the side, not the end, of each tarsus springs a long, 

 hyaline, slender peduncle, which projects considerably beyond the 

 tarsus ; this peduncle is flexible in all directions — uot in the sense 

 that it yields when it touches anything, for in effect it seldom does 

 touch anything except very lightly, but in the sense that it has 

 special motion of its own and can be flexed and turned in any 

 direction at the will of the creature ; indeed, it is almost constantly 

 in motion. The distal end of this peduncle swells suddenly and 

 forms a bulb, at the end of which is a very minute claw ; the bulb 

 can be turned upward and downward, carrying the claw, but the 

 claw has not any motion separate from the bulb. This claw and 

 peduncle are not used in clinging or walking at all ; they seem 

 to have become wholly tactile organs ; the creature clings with the 

 tarsus and then appears to feel about with the claw by turning 

 and bending its flexible peduncle in all directions until it finds a 

 suitable place to put the tarsus for the next step, then it moves 

 the tarsus and the pi'ocess recommences, being of course done 

 by opposite legs alternately. I am not aware of anything at 

 all similar in the structure and habits of any of the Acarina. 

 I propose calling the genus " Lentungula" and the species 

 L. cdyivorans. 



Genus Leniungula\ 



Tyroglyphid^e without marked sexual dimorphism ; with the 

 body flattened dorso-ventrally ; with the tarsi of the two front 

 pairs of legs strongly curved, gradually diminished, ending in 

 points, and used as climbing-organs. The claws of the same pairs 

 of legs minute and mounted on long flexible peduncles springing 

 from the sides of the tarsi and capable of being flexed at the will 

 of the creature. Tarsi of two laind pairs of legs of the ordinary 

 type, ending in large single claws without caruncles. With terminal 

 anus formed of two upright plates lying against each other. 

 Genital aperture in both sexes near the middle of the body 

 between the coxae of the foiu"th pair of legs. 



^ Lentus, flexible ; ungula, a little claw. 



