. 147 



n comb. The square plate with its fingers must be 

 Jurine's third pair of feet ; though, if so, the figure which 

 this author gives of these organs, as well as of his second 

 pair of feet (the palpi of the mandible of Straus), is de- 

 cidedly incorrect.* The second pair of jaws is much smaller, 

 and is articulated on to the posterior angle of sternum, 

 by means of the two curved apophyses at its extremity 

 (t. XVIII, f. I/). Each jaw consists of two flattened 

 joints, the latter of which has several stiff hairs at its 

 extremity, and from its external edge gives off a rounded 

 finger, which Straus says he thinks must be considered 

 as a palpus. 



There is much discrepancy amongst the several authors 

 I have so frequently mentioned as to the number of feet. 

 Miiller and Ramdohr assert there are four, and the former 

 remarks upon the singularity of an insect quadruped. 

 Straus enumerates six ; while Jurine says there are eight, f 

 M. Edwards however restricts, very properly, the number 

 to two pairs. The first pair (t. XVIII, f. 1 g) is slender, 

 cylindrical, and composed of five articulations ; the last 

 of which is terminated by one long curved hook. The 

 basilar joints of these organs are directed backwards ; the 

 succeeding joints downwards, and the terminating ones 

 forward. The second pair (t. XVIII, f. 1 Ji) arises imme- 

 diately behind the first, and consists of four articulations,! 

 the last of which is terminated by two short hooks, and 

 has a filament thrown back from its extremity like a spur. 



* He seems to have been ignorant of the existence of the branchial plate, 

 as he asks, " If it be true that the branchiae be the first character of the 

 Crustacea, where shall we place them in these Monoculi ? In the antennae, 

 feet, or tail ? We cannot give a preference to any one of these parts over 

 another." 



f Miiller was not aware of the existence of the organs which Straus calls 

 the third pair of feet. Ramdohr was, but considers them as connected with 

 the male organs of generation ; while Jurine says that they are organs arising 

 from the matrix, the use of which he does not understand. In addition to 

 the first and second pairs of Miiller, Ttamdohr, and Straus, Juriue considers 

 the organs which Miiller calls the " barbillons," attached to the mouth (the 

 palpi of the mandibles of Straus) and the branchial plate of the upper jaw, 

 as two additional pairs of feet. 



J Straus says five. 



