MACRURA. SCII MITT. 331 



The petasuia is symmetrical and, though relatively 

 of a somewhat heavier build, is in general much like 

 that of P. inter medi us. As seen from below, the antero- 

 lateral spine of the terminal portion of each moiety is 

 quite strong and prominent, and considerably over- 

 reaches the rounded protuberance of the inner distal 

 angle. The spine is as long as the anterior margin of 

 the terminal piece. Adjacent to the spine on its inner 

 side, is a smaller spine-like projection of which there is 

 no counterpart in P. inter mcdius', in this latter species 

 also the antero-lateral spine is subequal to, or a little 

 shorter than the median protuberance. In P. intermedium 

 there is an indication of a small point on the outer 

 proximal margin, which is not found in P. endeavouri; 

 on the other hand, the proximo-lateral angle of the 

 terminal portion of P. endearouri is prominently pro- 

 duced backward and outward in a slightly flattened, 

 twisted lobe, while in P. intermedium the same angle is 

 merely rounded off. 



The thelycuni lacks the posterior median point, or 

 tubercle characteristic of P. intermedius which is so 

 well shown by Ealss, 22 and the lateral plates are not bent 

 to form a right angle about the middle of their length ; 

 nor do they form so sharp a. ridge, being very blunt and 

 more or less evenly rounded off in ventral aspect. They 

 are also separated by a wider interval on the median 

 line. Furthermore, the posterior extensions of the 

 fourth pair of legs of P. inter mcdius not only overhang 

 the ^teral plates of the thelycuni, but they much surpass 

 them in prominence and conspicuousness. In 

 P. endeavouri on the other hand, they are quite sub- 

 ordinate in size and position to the lateral plates. The 

 median anterior plate of the thelycuni, like that of 

 P. intermedius, is labiate, but not so broadly so anteriorly, 

 and, in direct contrast to that species, is slightly 

 emarginate in the middle of the anterior margin. At this 

 point in P. intermedium there is a small blunt tooth or 

 prominence. 



Size and Measurements. This species appears to 

 attain a larger size than P. intermedius. Of three speci- 

 mens of the latter before me, two females measure 120 

 mm. in length and a male is 110 mm. long. Kishinouye's 



22 Balss, Abh. der K. Bayer. Akad. Wiss., ii., Math. phys. 

 Klasse. Suppl., 9 Abh., 1914, p. 8, fig. 2. 



