SCYLLARUS SCULPTUS, LATR. WHITELEGGE. 157 



many more were secured by wading and pulling up the seaweeds 

 from deep holes. The plants were carried up above high water- 

 mark, and left for an hour or so to dry. The drying has the effect 

 of loosening the hold of the Isopods, and they may be readily 

 detached by shaking the plants. 



The following is a complete description of S. sculptus : — 

 ScYLLARUS SCULPTUS, Latreille. 



Scyllarus sculptus, Latr., Encyclopedie M ethodique, pt. 24, 1818, 

 pi. eccxx., fig. 2, and x., 1825, p. 416; Milne Edwards, 

 Hist. Nat. Crust., ii., 1837, p. 283. 



Adult male. — Carapace 90 mm. in length, the width of the front 

 between the orbits 49 mm., that of the entire frontal margin (spines 

 included) 81 mm., and that of the hinder margin 77 mm. ; the 

 greatest width is in a transverse line with the posterior cardiac 

 region. 



The rostriform process is slightly depressed, somewhat emarginate 

 anteriorly, with obtuse lateral angles ; its length is about 5 mm., 

 its breadth anteriorly 6'.5 mm., and its narrowest part is just 

 above the base and measures 4 mm. It is bounded externally on 

 each side by a transversely elongate C-shaped depre.ssion, into 

 which the somital lobes are dove-tailed and appear to be fused 

 with the carapace. Each lobe has about eight or nine rounded 

 tubercles on the posterior border, a pair on the anterior externally, 

 and a prominent wide based denticle about the middle ; its sides 

 slope away to the rostrum and to the external pair of tubercles. 

 The length of the lobe is 5 mm., and its width 10 mm. 



Lateral frontal margins deflexed, slightly curved, the inner 

 extremity ending in a low tooth, the base of which is situated 

 under the external portion of the somital lobe ; the outer portion 

 of the margin curves upwards and terminates at the rather pro- 

 minent interno-orbital spine. The orbits are well defined ; the 

 cavity beneath the cornea is margined with long hairs. The 

 inner portion of the superior border is elevated and bears three 

 prominent spines and as many low tubercles ; centrally there is a 

 pair of tubercles bounded on each side by a sinus, and the outer 

 portion has a series of four tubercles and a spine at the angle. 

 Anterior to the latter is a wide sinus, and a large spine-like process 

 which arises from a point near the insertion of the second antenna 

 and forms the outer boundary of a large anterior orbital fissure ; 

 the inner side is limited by descending process of the front. The 

 base of the fissure is occupied by a lobe a little higher than broad 

 at the base, and uni- or bituberculate at the summit. 



The upper surface of the carapace bears a few more or less 

 acute spines, and is closely covered with flattened scale-like 

 tubercles ; each tubercle is fringed anteriorly with short stiff setae, 



