20G J. Wood-Mason — l)escription of Lyreidus clianneri. [No. 2, 



XIII. — Natural History Notes frorti H. M.^s Indian Marine Survey 

 Steamer ' Investigator,' Commander Alfred Carpenter, R. N. 

 Commanding. No. 4. Description of a neio Species of Crustacea he 

 longing to tlie Brachyurous Family Raninidse. — By J. Wood-Mason 

 Esq., Superi7itendent of the Indian Museum, and Professor of Com 

 parative Anatomy and Zoology in the Medical College of Bengal 

 Calcutta. 



[Keceived and Read August 5th, 1885.] 



(With Plate I.) 

 Lyreidus channeri, n. sp. 



Proc. Asiat. Soc. Bengal, August 1885, p. 104. 



cT . Carapace transversely moderately convex, longitudinally blunt- 

 ly carinate and slightly arched from near the posterior margin almost to 

 the level of the spines marking the commencement of the antero-lateral 

 margins, from which level to the end of the rostrum it is slightly con- 

 cave ; its antero-lateral margins armed with two pairs of long slender 

 and acute outwardly and forwardly directed spines, of which the pos- 

 terior are nearly twice the length of the anterior pair (the left one of 

 which has been broken off early in life and is now only represented by a 

 tubercular scar) : its sides parallel from the larger pair of spines back- 

 wards to the insertion of the chelipeds, whence they gradually and re- 

 gularly converge to the rounded angles of the concave-truncate posterior 

 margin ; and rapidly convergent from the same pair of spines forwards 

 to about the level of the middle of the 3rd joint of the external maxil- 

 lipeds, whence they suddenly run parallel to, or slightly divergent from, 

 one another to the ends of the extraorbital spines. The rostrum is 

 semi-oval, or, in other words, has the form of a triangle with the apex 

 rounded and the opposite sides slightly arched, and, like the eye-pe- 

 duncles, is surpassed by the long and acuminate extra-orbital spines. 



Immediately in front of the two small crescentic muscular impres- 

 sions near the middle of its length, the carapace is crossed by a faint 

 depression, interrupted by the median carina and continued on the 

 sides, passing immediately in front of the junction of the finely beaded 

 postero-lateral lines with the linea anomurica some distance to the rear 

 of the hinder pair of antero lateral spines, and deepening as it goes, to 

 the buccal frame ; in front of this depression the puncture of the surface 

 is much coarser and thicker than behind it. The antero-lateral margin 

 is finely granulated and, with the contiguous subhepatic and anterior 

 pleural regions, slightly hairy. Two faint depressions, marking out a 

 cardiac region, pass oli" from the posterior ends of the crescentic im- 



