179 



3. Poreellio dilatatus, Brandt. 



(PI. LXXVIII, fig. 2.) 



Poreellio dilatatus, Brandt & Katzeburg, Meclicin. Zoologie, Vol. II, p. 78, El. 12, fig. b'. 



Syn: Poreellio scaber, M.-Edw. (not Latr.). 



Specific Characters. — Body broadly oval, not nearly twice as long as it 

 is broad, dorsal face moderately convex, and rougb owing to rounded elevated tu- 

 bercles, especially densely crowded in the middle of the segments. Cephalon with 

 the lateral lobes large, obtusely truncated at the tip, frontal lobe distinctly pro- 

 jecting, obtusely triangular. Side-plates of mesosome rather large, with the 

 posterior corners obtusely acuminate. Metasome nearly twice as broad as it is 

 long, and scarcely attaining '/* of the length of the body, epimeral plates of 3rd 

 to 5th segments greatly prominent, semilunar; last segment nearly as long as. it 

 is broad at the base, outer part considerably produced and plane above, tip ob- 

 tusely rounded. Antennae rather strongly built, 2nd joint of the peduncle much 

 dilated, flagelluna shorter than the last peduncular joint, and having its articula- 

 tions subequal in length. Legs comparatively short and thick. Opercular plates 

 of the 2 anterior pairs of pleopoda with air-cavities. Uropoda with the outer 

 ramus rather broad, inner ramus scarcely extending beyond the last caudal seg- 

 ment. Colour of dorsal face dark slaty grey, the segments of mesosome ex- 

 hibiting on each side of the median line an assemblage of irregular, somewhat 

 lighter jjatches. Length of adult female 14 mm. 



Remarks. — Though rather nearly allied to P. scaber, with which it was 

 confounded by M. -Edwards, this form may be easily recognized by its unusually 

 broad body, and by the shape of the last segment of the metasome. 



Occurrence. — A well-marked adult specimen of this form, the one here 

 delineated, was sent to me from conservator Storm, who found it in a garden 

 hot-house in Trondhjem. I have myself taken 2 not yet fully grown specimens 

 in the Botanical Garden in Christiania, likewise from a hot-house. It is slower, 

 in its motions than most other species. 



Distribution. — Denmark, Germany, Poland, Holland, Britain, France, 

 Triest, New Guinea, Australia. 



