18 



Polycheles sculptus. Smith. 



PL II, figs. 1-9. 



Polycheles sculptus, Smith, 1880 (a). 



Polycheles sculptus, Smith, 1880 (b). 



Pentacheles spinosus, Mihie-Edwards, 1880. 



Pentacheles sculptus, Smith, 1882. 



Polycheles sculptus, Caullen^ 1896. 



Pentacheles sculptus, Alcock and Anderson, 1899. 



Polycheles sculptus, Alcock, 1901. 



Polycheles sculptus. Senna, 1903. 



Polycheles sculptus, Stebbing, 1903. 



Polycheles sculptus, Hansen, 1908. 



The carapace is longer than the abdomen ; its sides are 

 almost parallel, but converge slightly in front and behind ; the 

 greatest breadth is just in front of the cervical groove. The latter 

 is deeper than in P. typhlops. The rostnim is form.ed of two 

 spines ; there is a spine at the inner angle of the orbital sinuses, 

 but not at the outer. The orbits are not of the same shape as 

 in P. typhlops ; their posterior part is not narrowed to a point, 

 but is rounded. The margins of the sinus are not denticulate. 

 The hind margin of the carapace is concave, and bears no spines 

 except the two in the centre, which are the last of the median 

 carina. The surface of the carapace is fairly smooth between the 

 spines. The oblique line running forwards and outwards from 

 the posterior cardiac region is without spines. The spiny 

 armature of the carapace is more robust than in typhlops and 

 is more constant in its arrangement. The spines of the median 

 carina are arranged thus : — R + 1,2, 1,; 2, 2, 2. On the lateral 

 margins there are six spines in the anterior part, three in the 

 central, and seven behind. They diminish in size backwards, 

 but are all larger than the corresponding spines in P. typhlops. 

 There is a curved row of five small spines extending from the 

 posterior end of the orbit to the cervical groove. There is also 

 a ridge furnished with five or six spines between the median 

 and lateral carinae ; it is not quite parallel to the lateral margin, 

 but curves shghtly inwards. Of the two submarginal carinae 

 the upper and outer one is very faint in its posterior part but 

 becomes more distinct in front, and ends in a prominent tooth 

 at the base of the antenna ; the inner and lower one bears a 

 row of well-developed teeth which decrease in size anteriorly. 



The abdomen .is broadest in its anterior part and tapers 

 uniformly to the telson. The first five terga are all keeled in 

 the median line. In the first segment the keel is not greatly 

 developed, in the second it is larger, in the third and fourth it 

 reaches a maximum, and in the fifth segment is slightl}^ smaller. 

 The dorsal median line of the sixth segment has a low unbroken 

 double ridge. The basal part of the telson has sometimes a 

 very small, blunt tubercle, but never anything like a well- 

 developed spine. The first tergum has two spines at its lateral 



