41 



species has not been figured, and neither, as far as I know, been found again, since it was 

 caught at Whampoa (China) living in holes of the mud, along the banks of the Canton River. 

 Its external maxillipeds seem to resemble mostly those of Dotilla and Tympanomerus^ and, 

 like these genera, it has tympana on the legs, but the abdomen of the cf is said to be like 

 that of Macrophthalmus^ viz. regularly and slightly tapering, not constricted in the middle. 



The genera of this subfamily have apparently all the same habits as those of the 

 preceding group : they indulge in digging burrows on sandy or muddy flats along the beach, 

 below the flood-line; occasionally some species are met with in fresh water. 



The following key is meant to discriminate the genera, save Ilyoplax : 



1. Body much globose, longer than broad. Posterior margin of 



carapace with a row of stiff bristles. Abdomen in both sexes 

 widening to tip, that is broadly truncate. No tympana on 



the legs Mictyris Latreille 



Carapace more quadrate, with elongate eye-stalks ; posterior 

 margin without a row of stiff bristles. Abdomen of cf normal, 

 tapering, often constricted in the middle. Mostly tympana on 

 the legs 2 



2. External maxillipeds of moderate size, not bulging, merus longer 



than ischium. Chelipeds of both sexes (especially of cT) stouter (. ii tr^i^^*^^ iX^>— /s^- 



than walking legs. Tympana absent or present Tympanomerus Rathbun 



External maxillipeds very large, with a strong, almost hemi- 

 spherical bulge forward. Tympana on the legs always distinct 3 



3. Merus of external maxillipeds longer than ischium. The distal 



end of the 4"^ abdominal segment of the cf is fringed with 



bristles, that overlap the next segment Dotilla Stimpson 



Merus of external maxillipeds shorter than ischium. 4'^ abdominal 

 segment of the 6" of normal size, but the next is more or 

 less constricted near the base Scopimera de Haan 



Mictyris Latreille. ^ 



1806. Mictyris Latreille. Gen. Crust, et Insect., t. i, p. 40. 

 1837. Myctiris H. Milne-Edwards. Hist. nat. Crust., t. 2, p. ^6. 



As far as I am aware, H. Milne-Edwards was the first to replace, apparently by error, 

 Mictyris by Myctiris^ and this latter spelling has been adopted by most subsequent authors. 



The two species, one with a wide Indo-Pacific range, the other only found at the coast 

 o*f East-Australia, Tasmania and New-Zealand, may be discriminated thus : 



Gastric region , of carapace nearly smooth. Postorbital spine 

 prominent. Chelipeds long, fingers about twice as long as 

 palm, upper and lower margin of palm carinate. Propodites 



of walking legs not much depressed M. longicarpus Latreille 



41 



SIBOGA-EXPEDITIE XXXIXC. 6 



