THYSANOrODA CRIST ATA. 211 



is medium sized, seen from behind (fig. If) considerably curved at the middle, 

 with the convex margin outwards and with the end compressed; seen from the 

 inner side (fig. Ig) the proximal lialf is besides a little curved, while a somewhat 

 short terminal part of the distal half is a little widened, very oblong, subacute 

 and bent to the left. The proximal process (p^.) overreaches considerably the 

 terminal; it is proportionately not thick at the base and tapers gradually towards 

 the other obtuse end; its distal third is very slender; it is curved somewhat 

 inwards at the end of its proximal fourth, while its distal half constitutes a 

 portion of a circle with the convex margin inwards. The median lobe (Im.) 

 is long and about its distal fourth is nearly lamellar; this lobe is produced dis- 

 tally with the tip rounded, and the lamellar part is bent inwards, covering, 

 seen from behind, the distal part of the lateral process. This process (p^.) is 

 very long, a little curved to the beginning of its terminal fifth, which is much 

 curved inwards and especially forwards and in reality considerably longer than 

 seen on the figures (figs, le and Ih) as the.se do not exhibit the process from the 

 inner side. The additional process (fig. Ih, which shows both the lateral and 

 the additional process seen from in front) is situated at the base of the lamellar 

 part mentioned; it is short, somewhat oblong, very thick to near the end which 

 is acuminate, acute, and somewhat curved. The auxihary lobe (lu.) is somewhat 

 short. The setiferous lobe (Is.) is nearly lanceolate with the end rounded and 

 with setae along both margins to their base. 



Length of the adult male 38 mm., of the two other specimens respectively 

 23 mm. and 18 mm. Sars's type measures 48 mm. in length. 



Remarks. — In 1907 I compared the largest specimen in the Agassiz col- 

 lection directly with Sars's type in the British Museum and found that they 

 agree perfectly with each other. Consequently Sars's figs. 15-16 are inaccurate 

 in various particulars of the carapace and the antennular peduncles. Sars 

 figured the rostrum bent downwards, but this is quite accidental, as the ros- 

 trimi is articulated to the frontal plate or broken at the base (see above). 

 Furthermore his fig. 15 exhibits a cervical groove and other furrows on the 

 anterior half of the carapace, but they do not exist, while he did not draw the 

 two short lateral impressions really existing and shown in my figures. He 

 figured the dorsal keel a little higher than in his specimen, and he overlooked 

 the denticle above the lateral margin somewhat from its posterior end. The 

 antennular peduncles are not well di-awn in his figures. Finally, his statement 

 on the length of his specimen (he states it to be 55 mm.) indicates that he here, 

 and probably elsewhere in his work, measured the animal from the end of the 



