344 asellidyE. 



Squilla asellus. De Geer, Ins. vii. t. 31, f. 1—20. 



Asellus vulfjaris. Latkeille, Hist. Nat. Crust, et Ins. vii. p. 359, 



t. 58, f. 1. Desmarest, Cons. Cnist. p. 314, 



t. 49, f. 1, 2. Milne Edwards, Crust, iii. 



p. 146. CuviER, R. An. (edit. Crochard) t. 70 



bis, f. 1. 

 Entomon Merocjlypldcum. Klin, Remarq. s. 1. Crust, fig. 5. 



This is a very common animal, occurring in fresh-water 

 ponds and ditches throughout the kingdom. The male 

 is much larger than the female. The head is about half 

 the size of the following segment ; its underside is nearly 

 covered by the large outer pair of foot-jaws, which con- 

 sist of an oblong flattened basal joint (furnished on the 

 outside, at the base, with a large semi-oval plate, Regne 

 An. Ed. Crochard Crust., pi. 70 bis, fig. 1 a, and Treviranus 

 Verm. Schr. t. xi. fig. 59 a, a), and five short terminal 

 joints, of which the first is produced into a lobe at its 

 inner extremity, and the last forms an acute finger-like 

 joint. The mandibles (Treviranus o. c. fig. 63) are 

 armed on the inside with a strong, horny tooth, and on 

 the outside with a three-jointed palpiform appendage. 

 The inner maxillae are described by the same author 

 (fig. 60) as only having two terminal setose lobes, and 

 the outer (fig. 61) as formed of two lobes, the inner 

 one much more slender than the outer. The bilobed 

 labium (fig. 62 z) lying between the base of the man- 

 dibles, is described by Treviranus as the third j)aii' of 

 maxillae. 



The ventral surface of the segments of the body, in 

 the males, is marked with strong transverse corrugations ; 

 in the female, it bears the large ovigerous sac, within 

 which the young are developed. The male, as is well 

 shown by Treviranus o. c. fig. 65 p. and 66 z, is fur- 

 nished with a pair of small and narrow curved horny 

 lobes in the middle of the hinder segment of the body, 



