4.28 A HISTORY OF RECENT CRUSTACEA 
more obtuse, scarcely prolonged backwards, with the 
lateral process small, obtuse ornone. All the four species 
agree with the species found in Syria in belonging to the 
division of the genus in which there are two pairs of 
tracheze, as distinguished from another division in which 
there are five pairs. The extensive distribution of Porcellio 
levis is emphasised by Budde-Lund in the words ‘Patria: 
Orbis terrarum.’ It was obtained by the Challenger at 
Bermudas, the Cape Verde Isles, and at Honolulu. M. 
Adrien Dollfus observes tkat while Porcellio scaher is 
abundant in the cold and temperate regions both north and 
south, but not in the tropics, Porcellio levis appears to 
have followed man all round the world except in the cold 
regions of the two hemispheres. 
Cylisticus, Schnitzler, 1853, has the body more convex 
and contractile than it is in the preceding genus. The 
branchial-opercula of all five pairs of pleopods are fur- 
nished with trachee. Cylisticus convewus (De Geer) has 
priority over the name Porcellio armadilloides, Lereboullet, 
used in the ‘ British Sessile-eyed Crustacea.’ Budde-Lund 
describes seven species of Cylisticus. 
Hemilepistus, Budde-Lund, 1879, is notable for ample 
sculpture with spines or coarse granulation on the front 
part of the body, of which, however, the young ones are 
devoid. Budde-Lund describes ten species, all of which 
are found in the sandy deserts of Africa and Asia. One — 
of them, Hemilepistus ruderalis (Pallas), was described by 
Pallas in 1771. The first and second pleopods, and more 
rarely the third or all are provided with trachez. 
Metoponorthus, Budde-Lund, 1879, meaning ‘with a 
straight front,’ is frequently mis-spelt Metoponorthrus, to 
which no intelligible meaning could be assigned. Budde- 
Lund gives descriptions of thirty-five species. In this 
genus is included Metoponorthus cingendus (Kinahan) found 
in the coast regions of England and Brittany, but dis- 
tinct from the species so named by Budde-Lund from 
the highlands of the South of France, which Dollfus has 
therefore renamed Metoponorthus meridionalis. This has 
three pairs of tracheze, whereas Kinahan’s species has only 
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