236 CRUSTACEA. 



They inhabit retired and obscure places, cellars, fissures in walls, old 

 buildings, under-stones, &c., &c. They feed on decaying vegetable 

 and animal matters, and seldom issue from their retreat except in 

 rainy weather. They move but slowly, unless they are alarmed. 

 The ova are inclosed in a pectoral pouch. The young, at birth, have 

 one thoracic segment less than the adult, and consequently have 

 but twelve feet. They are no longer employed inmedicine*. 



PORCELLIO, Lat. 



The Porcelliones ' differ from the Onisci in the number of joints 

 that compose the lateral antennae, which is only seven. In their 

 other characters they are alike f . 



There, as in 



ARMADILLO, Lat. 



The posterior appendages of the body do not project ; the last seg- 

 ment is triangular; a little lamina resembling a reversed triangle, or 

 widest and truncated at the end, formed by the last part of the late- 

 ral appendages, fills on each side, the space between that segment and 

 the preceding one. The lateral antennae have but seven joints. The 

 superior subcaudal scales exhibit a range of small holes J. 



SECOND GENERAL DIVISION. 



ENTOMOSTRACA. 



Under this denomination, which is taken from the Greek and sig- 

 nifies Insects with shells^ Othon Frederic Miiller comprises the genus 

 Monoculus of Linnaeus, to which we must add some of his Lernaeae 

 His investigation of these animals, the study of which is so much the 

 more difficult as they are mostly microscopic, and the observations of 

 Schreffer and of M. Jurine, Sen., have excited the admiration and 

 secured the gratitude of every naturalist. Other but partial labours 

 such as those of Randohr, Straus, Herman, Jun., Jurine, Jun., 

 A. Brongniart, Vistor Audouin, and Milne Edwards, have extended 

 our knowledge of these animals and particularly of their anatomy ; 



* Oniscu, murarius. Fab.; Cuv., Journ. d'Hist. Nat., II, xxvi, 11, 13; Le Clo- 

 porte ordinaire, Geoff., Insect. II, xxii, 1 ; Cloporte aselle, Deg., Insect. VII, xxxv. 

 3 ; Desmar. Consid., XLIX, 5. 



f Oniscus asellus, Cuv., Ib.; Panz., Faun. Ins. Germ., IX, xxi ; Cloporte ordinaire, 

 var. C, Geoff. ; Porcdlio locvis, Latr. ; Cloporte ordinaire, var. B, Geoff. 



\ Oniscus armadillo, L. ; Cuv., Ib., 14, 15 ; Oniscus cinercus, Panz., Ib., Fascic. 

 LXII, xxii ; Oniscus varieyatus, Vill., Entom., IV, xi, 16 ; Armadille pustule, Des- 

 mar., Consid., LXIX, 6 ; Armadille des boutiques, Dumer., Diet., des Sc. Nat., 

 Ill, p. 1 17, a species from Italy formerly employed by the apothecaries. 



