428 A HISTORY OF RECENT CRUSTACEA 



more obtuse, scarcely prolonged backwards, with the 

 lateral process small, obtuse or none. 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 

 trachea?, as distinguished from another division in which 

 there are five pairs. The extensive distribution of Porcellio 

 Icevis 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 that while Porcellio scaber is 

 abundant in the cold and temperate regions both north and 

 south, but not in the tropics, Porcellio Icevis 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 tracheae. Cylisticus convexus (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 ruder alls (Pallas), was described by 

 Pallas in 1771. The first and second pleopods, and more 

 rarely the third or all are provided with trachea?. 



Metoponorthus, Budde-Lund, 1879, meaning 'with a 

 straight front,' is frequently mis-spelt Metoponortlirus, 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 trachea?, whereas Kinalian's species has only 



