RATHBUN— MARINE BRACHYURA 245 



orbit without spine. Median gastric elevation conical and blunt ; lateral elevations low 

 and small. The conical hepatic projection terminates in an outward-pointing cylindrical 

 spine and bears a spinule on its anterior border. The margin between the orbits and the 

 hepatic region shows several minute spinules. The cardiac region has 2 large tubercles 

 side by side and a very small one on the posterior slope. There is a large low tubercle on 

 the branchial region just in front of the base of the last leg ; also a small sharp spine 

 pointing downward and a little forward, just below the antero-lateral margin of the 

 branchial region. A small pterygostomian spine shows slightly in dorsal view in the 

 sinus between hepatic and branchial regions. 



The long slender eye-stalks have a small tubercle on middle of anterior margin and 

 an outward-pointing spinule above near end of eye. Basal joint of antenna spinulous ; the 

 next segment reaches a little beyond tips of rostrum ; the third is as long as the first ; 

 movable portion of antenna half as long as carapace, and fringed on each side with long 

 hair. A spinule on lower surface near angle of buccal cavity. 



The last or coalesced segment of the abdomen bears a spinule at its middle. 



Chelipeds stout in the full-grown males, fringed with long hair on their inner edge ; arm 

 with margins spinulous. Wrist with a row of curled hairs and spinules along the supero- 

 external border, the proximal spinules largest. Hand with a few very small spinules 

 above and some curled hairs on the outer surface. Immovable finger arched downward so 

 that the fingers gape strongly in their basal half, the small truncate tooth at the base of 

 the dactyl fits against, and distal to, an acute tooth on the end of the palm, pointing 

 obliquely upward. Fingers fringed with long hair in the gape ; the distal portions where 

 the fingers meet are finely crenulate, and the immovable finger bears a tooth at the distal 

 end of the gape. Dactyli of first two legs long and slightly curved ; of last two legs short 

 and very strongly curved. The first 3 of the long segments are furnished with curled 

 hairs, while the propodi and dactyli have some long straight hairs, most numerous about 

 the distal articulation of the propodi of the last two pairs. 



Dimensions of $ in mm. : 



C. 1. 6-6. 



C. b. 4-5. 



R. 1. (from front edge of orbit) 1. 



Antenna, free portion, 3'3. 



H. 1. 37. 



H. b. 17. 



W. L. 1. 32-5 ; merop. 1. 10-3 ; carp. 1. 4 ; prop. 1. 10 ; dact. 1. 6. 



W. L. 2. 32 ; merop. 1. 10 ; carp. 1. 4"5 ; prop. 1. 9"4 ; dact. 1. 5"8. 



W. L. 3. 25 ; merop. 1. 9"5 ; carp. 1. 5 ; prop. 1. G"5 ; dact. 1. 2'1. 



W. L. 4. 19-5 ; merop. 1. 7'6 ; carp. 1. 4 -8. ; prop. 1. 4 '6 ; dact. 1. 1 '8. 



In the $, the chelipeds are slender and the fingers meet throughout their length. 



Having been able, through the courtesy of Dr. Caiman, to examine a cotype of Achmts 

 affinis Miers ($ from Thursday Island) in the British Museum, I find that the present 

 species is quite distinct; the carapace more slender, the horns sharper, the chelipeds 

 stouter with gaping fingers and the legs longer. 



