22 



far over the preceding segments. The tergum of the sixth 

 segment is marked by a double ridge, the edges of which are 

 broken up into jagged teeth. On the basal part of the telson 

 there is a sharp tooth with a very small tubercle on its posterior 

 edge. The terga of the second to fifth segments have a deeply 

 chiselled groove on each side, sloping upwards and forwards 

 from the postero-lateral angle. The relative proportions of the 

 pleura of the diiferent segments are as in P. sculptus. In the 

 present species, however, the lower edges of the pleura are 

 minutely serrate. All the pleura are fringed with setae, as are 

 also the telson and uropods. 



The eyestalks have a small tubercle on the anterior edge, 

 but sometimes it is very indistinct. At the posterior end of the 

 orbital sinus there is a small translucent area on the eyestalk 

 as there is in P. sculptus. 



The basal joint of the antennular peduncle has two spines 

 at its outer anterior angle. The outer flagellum is shorter than 

 the peduncle and very slender. The inner flagellum is as long 

 as the antennae, and longer than the carapace. 



The chelipeds are extremely slender and compressed. They 

 are much shorter than in P. sculptus. The merus bears a small 

 spine on the proximal part of the upper margin, and also one 

 at the distal extremity ; the carpus also has a dorsal distal spine. 

 All five pairs of pereiopods are chelate in both male and female. 

 The pleopods are similar to those of the species already de- 

 scribed. 



The three specimens taken by the Helga are all females, one 

 of them ovigerous, and belong to the var. Grimaldii, Bouvier. 



Size : — The largest specimen taken by the Helga measures 

 74 mmx., exactly the same as Hansen's largest specimen. Faxon 

 took an ovigerous female only 58 mm. long, so the size of the 

 adult forms is considerably less than in P. sculptus. 



The following measurements are taken from the large ovigerous 

 specimen. 



Length 



Length of carapace 

 Length of abdomen 

 Breadth of carapace 

 Length of chelipeds 

 Length of ischium of chelipeds 

 Length of merus of chelipeds 

 Length of carpus of chelipeds 

 Length of propodite of chelipeds 

 Length of palm of chelipeds 

 Length of dactyl of chelipeds 

 Length of second pereiopods 

 Length of third pereiopods 

 Length of fourth pereiopods 

 Length of fifth pereiopods 

 Length of antennules . . 

 Length of antennae 



74 



mm. 



31 



mm. 



43 



mm. 



23 



mm. 



73 



mm. 



14 



mm. 



22-5 



mm. 



12 



mm. 



23-5 



mm. 



10 



mm. 



13-5 



mm. 



29 



mm. 



26 



mm. 



23 



mm. 



20 



mm. 



41 



mm. 



33 



mm. 



