678 



])ocl:i scarcely differing in their structure from those limbs in the genus Aristias. 

 Telson, however, rather different, being entire, without any cleft. Sexual 



difference very slight. 



Eemarlis. The present genus was established in the year 1892 by 

 MM. Chevreux and Bouvier, to include a form, which at first was believed to 

 be new to science, but was subsequently shown by M. Bonnier to be the true 

 Li/sianassa audouiniana of Sp. Bate. In the same year, though perhaps a little 

 later, Mr. Robertson examined the same form, and proposed for its reception 

 the new genus Pararistias. The genus is indeed very closely related to Ari- 

 stias, but may perhaps be retained on account of some differences occurring 

 in the structure of the oral parts, and especially on account of the very 

 differently shaped telson. It contains as yet but a single species, to be de- 

 scribed below. 



Perrierella audouiniana, (Sp. Bate). 



(Suppl. PI. II, tig. 2). 

 Lysianasaa audouiniana, Sp Bate, Catal. of Amph. Brit. Mus., p. 69, PI. XI, fig. 1. 



Syn. : Aristias audouinianus, Meinert. 



Perrierella crassipes, Chevreux & Bouvier. 

 Pararistias audouinianus, Robertson. 



Body short and compact, with broadly rounded back. Cephalon about 

 the length of the 1st segment of mesosome and rather deep, with the anterior 

 edges somewhat convex, lateral corners slightly produced at the tip. Anterior 

 pairs of coxal plates scarcely as deep as the corresponding segments; 1st pair 

 small, and to a great extent covered by the 2nd, which are of a rounded 

 oval form, with the distal edge slightly serrated ; 3rd pair somewhat expanded 

 distally; 4th pair of an irregular rhomboidal shape; the 2 succeeding pairs 

 much smaller, and having the posterior lobe deeper than the anterior. Last 

 pair of epimeral plates of metasome angularly produced at the lateral corners. 

 Urosome short and stout. Eyes rather large, and of a somewhat oval form, 

 being slightly narrowed above, pigment dark, with a chalky white coating. 

 Superior antennae about the length of the cephalon and the first 2 segments 

 of mesosome combined, joints of the peduncle rapidly diminishing in size, 

 flagellum much shorter than the peduncle, and composed of 4 articulations 

 only; accessory appendage rather small, biarticulate. Inferior antennae with 

 ilagellum very small, not even attaining the length of the last peduncular 

 joint, and 4-articulate. Anterior gnathopoda rather strong, propodos exceeding 



