62 Bibliographical Notices. 



of no great strength. The third pleon segment is produced 

 backwards in a rounded lobe formed by the hinder and 

 lower margins. The three following segments are very 

 small, carrying slender uropods, decreasing in size from the 

 first to the third pair. In all the rami are minutely serrate. 

 In the first pair the peduncle is long, but in the third it is very 

 short. 



The huge boat-shaped telson reaches as far back as the tip 

 of the shorter branch of the third pair of uropods. 



The colour in the mounted specimens was a beautiful red 

 in some parts and purple in others ; the size, a tenth of an 

 inch, agrees with the diminutive proportions of the other 

 species of this curious genus. 



EXPLANATION OF PLATE II. 



Full figure, side view of specimen less than ^ inch in length. Antennae 



and gn. 1 A from another specimen, the remaining figures from a 



third (dissected) specimen, drawn under the i-inch power, eyepieces 



A and B, of Beck's popular microscope. 

 a. s., flagellum of superior antenna, mx. 2, second maxilla. 

 a. i., antenna inferior. mxp., maxilhpeds. 



I. s., lahium superius. gn. 1, first gnathopod. 



l.i., labium int'erius. gn. 2, second gnathopod. 



in. m,, mandibles: figure on the left prp. 1, 3, 4, 5, first, third, fourth, 



with cutting-edge aud spine- and fifth perseopods. 



row ; figure on the right with T, telson, with third and second 



cutting-edge and secondary uropods. 



plate, more highly magnified. ur. 1, first uropods. 

 mx. I, first maxilla. n. s., natural size. 



BIBLIOGRAPHICAL NOTICES. 



British Oribatidce. By Albert D. Michael, F.L.S., F.B.M.S., &c. 

 Yol. I. 8vo. London : Printed for the Bay Society, 1884. 



Its the Preface we are told " that this hook is the record of work 

 clone in the scanty leisure of a very busy man." The author has 

 for some five years turned his attention to the Oribatidse, a family of 

 Acarina commonly known as " Beetle-mites," in allusion to their 

 usually convex beetle-like form and the hardness of their integu- 

 ments. Little was known of them or of their earlier stages, for, like 

 many other Mites, they undergo a series of changes after emerging 

 from the egg, or, in other words, they pass through larval and 

 nymphal stages to the imago, so that in the majority of cases " it 

 would be impossible to identify the nymph with the adult except 

 from knowledge." Thus it was necessary to watch the animals from 

 the egg to maturity. "The creatures," says our author, "are minute, 

 scarcely visible at all to the naked eye. When in the cage (or cell) 



