208 J. WoodMa.son—DesGripHo7i of Ljreidus channeri. [No. 2, 



The unique example from whicli the foregoing description has been 

 drawn up measures : — 



millims. 



Length of carapace from tip of rostrum to posterior margin 25.0 



j5 jj „ a to the middle of a straight 



line joining the bases of the posterior spines 8.5 



Length of carapace from the posterior margin to the same straight 



line 16.5 



Breadth of carapace across the parallel-sided part 14.3 



Breadth of head between tips of extra-orbital spines 6.0 



Distance between tips of posterior antero-lateral spines 18.0 



Length of posterior antero-lateral spines 5.0 



„ ,, anterior antero-lateral ,, 3.0 



,, ,, genital appendages 5.5 



„ ,, rostrum, measured from a straight line drawn tangen- 



tially to the bottom of the supra-obital emarginations, 2.0 

 „ „ extra-orbital angles, measured from the same straight 



line, 3.4 



This interesting brachyuran may at once be distinguished from 

 either of the three previously described species of its genus (L. triden- 

 tatus, DeHaan, Faun. Jap. Crust. 1850, p. 138, tab. XXXV, fig. 6, d', 

 L. elongatus, Miers, Proc. Zool. Soc. Lend. 1879, p. 45, both from the 

 seas of Japan, and L. halrdii, S. I. Smith, Proc. U. S. Nat. Hist. Mus. 

 1881, III, p. 420, from 100 fathoms, off the South Coast of New Eng- 

 land) by the conspicuous armature of its carapace, by its bispinose ab- 

 domen, and by its partially aborted eyes. 



A single male only of it was dredged up in the trawl from a depth 

 of 405 to 285 fathoms with a bottom temperature of 48" to 50' Fahr. 

 in the ' swatch-of -no-ground,' a deep and narrow valley running north- 

 wards from the floor of the Bay of Bengal to within a short distance 

 of the shoals lying off the conjoined mouths of the Ganges and 

 Brahmaputra, in Lat. 21° 6' 30" N., Long. 89° 20' E. 



Explanation of Plate I. 



Fig. 1. Lyreidus channeri, W.-M., cf. Natural Size. 



,, 2. Orbital, antennary, and buccal view, x 2. 



,, 3. Four terminal somites of abdomen, seen from below as they lie closely 

 applied against the underside of the cephalothorax. x 3. 



„ 4. Dorsal view (to the right) of the abdomen, with side view (to the left) of 

 its spinigerous 3rd and 4th terga. x 3. 



„ 5, 5a, Outline views from above, or optic sections in the plane of the fringing 

 setffi, of the left and right eye-peduncles respectively, to show (a.) the 

 setae that fringe their two margins up to the corneal membrane on each 

 side ; (/).) the thickness and the relative development of the cornea, 



