622 THE VOYAGE OF H.M.S. CHALLENGER. 



what tooth this author means by " les epines suborbitals. " If it refers to that which 

 we call the antennal tooth, it differs from our species which has that tooth short in 

 relation to the length of the ophthalmopod ; but as it is not impossible that it was 

 intended to mean the stylocerite, which in its proper position lies under the orbit and 

 supports the eye, then it corresponds with the description (depassant les yeux et atteignant 

 le tiers ante'rieur du rostre). 



Arnpliiplectus. 1 



Resembles MerMppolyte, but differs in the proportional size of the second pair of 

 gnathopoda, the first two pairs of pereiopoda, and in the form of the mandible. 



The second pair of gnathopoda is short, feeble, and furnished with a long and 

 slender basecphysis. 



The first pair of pereiopoda is also short, feeble and chelate. The second pair is more 

 than twice the length of the first, and has the basal joint robust and the distal joints 

 slender ; the carpos is long, divided into numerous small articuli, and the terminal chela 

 is slender and feeble. 



The mandible has the molar process and psalistoma confluent, the former being the 

 lower and robust portion, and the latter forming the upper and more thin division of the 

 anterior serrate margin, from the base of which a two-jointed synaphipod arises. 



The pleopoda are subfoliaceous, biramose, and lanceolate in form. 



The rhipidura has the outer plate a little longer than the telson, rounded at the 

 extremity and armed on the outer margin with a sharp tooth and a spinule at the 

 extremity of the diaeresis. 



The telson is long, slender, tapering to the extremity and distally truncate. 



The branchiae consist of a series of pleurobranchise and arthrobranchiae as shown in 

 the annexed table : — 



Pleurobranchife, 

 Arthrobranchiee, 

 Podobranchise, 

 Masti Kobranchiae, 



Observations. — This genus bears a strong resemblance to Merhippolyte, from which it 

 differs in the feebleness of the limbs, especially the anterior ones. 



It also resembles Nematocarcinus in the peculiar articulations that exists between 

 the ischium and meros, although the great length of the legs is wanting. The carpos 

 in the first two pairs of periopoda is also similar, but in the three posterior pairs this 



1 xfitpiK*rix.Tog, compressed on both sides. 



