48 Prof. Allman on a new genus and species 



rounded at its posterior end, of a white colour, and causing the 

 animal at first sight to suggest the idea of a small grain of rice. 

 The oral apparatus is in the form of a proboscis situated on the 

 under surface of the anterior end of the cephalothorax, and is 

 composed of a pair of didactyle mandibles ensheathed by an upper 

 and lower lip. The mandibles (fig. 2 a & fig. 3) are composed of 

 two elongated articulations, with a minute terminal one which is 

 opposable to a prolongation of the external side of the articula- 

 tion which precedes it, so as to constitute a small prehensile for- 

 ceps. The lower lip (fig. 2 b) is very large ; it is deeply divided 

 in the centre, conceals the bases of the mandibles, and supports 

 at each side a filiform palp (fig. 2 c) with four free articulations. 

 The upper lip is arched in front, and presents upon its external 

 surface the appearance of two subulate organs converging towards 

 the mesial line of the lip (fig. 4) . 



The oral organs are immediately succeeded by four pairs of six- 

 jointed legs. Of these the anterior pair is a little longer and 

 more slender than the second and third, and is directed forwards 

 on each side of the proboscis so as to resemble a pair of antenna?. 

 The fourth pair is also slightly more slender than the two which 

 precede it and is directed backwards. The first three pairs arise 

 close to one another ; the fourth is separated from the third by a 

 disproportionate interval. All the legs support, upon the distal 

 extremity of their last articulation, a pair of strong recurved hooks 

 with an intermediate three-lobed caruncle (fig. 5). 



Upon the under surface of the cephalothorax may be observed, 

 with the assistance of a low magnifying power, four small brown 

 puncta ; these, as will be presently seen, are the lateral lobes of the 

 great central nervous mass appearing through the integument. 



On the dorsal aspect of the cephalothorax and extending for 

 some distance behind the origin of the posterior pair of legs is a 

 corneous shield of a somewhat oval shape with sinuous margins 

 (fig. 6), and on the ventral aspect a sternal plate may also be 

 demonstrated, though this can scarcely be distinguished from the 

 surrounding soft integument. If however the floor of the ce- 

 phalothorax be separated and then viewed under compression by 

 transmitted light, a distinct plastron (fig. 7) may be easily seen, 

 having its posterior margin produced into two long processes 

 which pass backwards, and its anterior into two shorter ones which 

 are directed forwards. To the four processes the muscles are at- 

 tached which move the legs. The muscular fibre is marked with 

 very evident transverse strise. 



The alimentary canal at its commencement seems to be an 

 exceedingly narrow tube, but it would afterwards appear to un- 

 dergo enlargement, and even to be furnished with extensive csecal 

 prolongations. Appearances would lead one to suspect that cseca 



