188 



above-described genus Cylisticus. Yet there are some characters which seem to 

 distinguish all the forms belonging to this family, viz, the peculiar structure of 

 the caudal segment and of the uropoda, as also the comparatively short antennae 

 and legs. Moreover, Mr. B.-Lund has stated that the young leave their mother 

 in a more advanced stage of development than in other Oniscoida, having all 

 the 7 segments of the mesosome well defined. According to the same author, no 

 marsupial pouch is formed in the female. But this may be less correct, as I 

 have found in one specimen of Armadillidium pictum distinctly [developed incu- 

 batory plates. Mr. B.-Lund refers to this family 8 different genera, and 2 more 

 are added by Mr. Dollfus, increasing the number to 10 in all. Of these, only a 

 single genus is represented in the fauna of Northern Europe. 



Gen. Armadillidium, Brandt, 1830. 



I 



Generic Characters. Body oblong or elliptical in form, very convex, and 

 capable of being rolled up into a perfect ball. Cephalon with the front distinctly 

 marginate, lateral lobes rounded, and sharply defined at the base. Epistome ver- 

 tical, forming above a triangular shield, advancing more or less beyond the frontal 

 edge. Side-plates of 1st segment of mesosome large, securiform, not incised 

 behind. Metasome semicircular, with the edges continuous throughout; last seg- 

 ment lamellar, quadrangular or triangular in form, not extending beyond the 

 limits of the epimeral plates of the penultimate segment. Eyes distinct, lateral. 

 Antennulse with the terminal joint but little produced. Antennae, as a rule, not 

 attaining half the length of the body, penultimate peduncular joint scarcely longer 

 than the 2nd ; flagellum biarticulate. Opercular plates of only the first 2 pairs 

 of pleopoda with air-cavities. Uropoda very short, with the basal part broad, 

 lamellar, outer ramus spatulate, inner narrow, cylindric. 



Remarks.- This genus, established by Brandt, is easily distinguished 

 from Cubans (Armadillo), with which it was formerly confounded, by the non- 

 incision of the anterior side-plates of the mesosome, and by the broad, spatulate 

 form of the outer ramus of the uropoda. It comprises numerous species chiefly 

 from southern Europe, amounting, according to B.-Lund, to more than 30 in all. 

 Of these, only 4 species are represented in the fauna of northern Europe, and 

 will be described below. 



