80 CARCtNOLOGICAL STUDIES. 



The proportion of the greatest width of the cephalothorax 

 to its length is in our specimens as 7:5. The upper surface 

 is slightly convex longitudinally as well as trans- 

 versely ; the gastric region is defined posteriorly by the 

 distinct cervical suture , but laterally by shallow depressions 

 of the upper surface. Similar depressions border the anterior 

 branchial area posteriorly and also for a part the cardiac 

 region. The upper surface appears smooth and shining to 

 the naked eye ; when seen under a maguifying-glass of suffi- 

 cient power, it appears however to be very minutely granular, 

 especially on the branchial regions. The postero-lateral sides 

 of the upper surface are marked with two minutely 

 granulated, pubescent, longitudinal lines, 

 which run parallel with each other, not far from the postero- 

 lateral margins ; a third , minutely granulated and pubescent, 

 though much shorter line runs, on each side of the upper 

 surface , in an oblique direction , close to and nearly parallel 

 with the posterior margin of the cephalothorax, immediately 

 above the insertion of the last pair of legs ; finally, a fourth , 

 somewhat arcuate line is seen immediately in front of 

 the two described longitudinal lines , proceeding, for a short 

 distance, transversely from the third tooth of the lateral 

 margins. The front is obliquely deflexed and shows a 

 longitudinal groove in the middle; it is rather narrow and 

 its breadth measures not quite one sixth of the distance 

 between the external orbital angles. The anterior margin 

 of the front is very slightly arcuate. The lateral margins 

 of the cephalothorax are sinuous, their anterior half being 

 slightly convex, their posterior portion appearing slightly 

 concave immediately behind the third lateral tooth. The 

 anterior half of the lateral margins presents two incisions, 

 the first of which is much larger and deeper than the 

 second. The first antero-lateral lobe has an obtuse or 

 sometimes even rounded external angle, which is the 

 external one of the orbits, towards which the upper 

 margin of the latter slightly rises upward. The second 

 lobe of the lateral margins is almost twice as long as the 



Notes from the Leyden ]Museuoi, Vol. XII. 



