230 A HISTOKY OF RECENT CEUSTACEA 



vnrleiies of one great type.' In Ghjiihocrcvngon acideatitSy 

 A. Milne-Eclvvarris, the carapace is ornamented with eight 

 carina, but in Gli/phocrangon granulosus^ Spence Bate, 

 there are five on each side of the median line, besides a 

 small central one on the rostrum. The telson in this 

 genus is described as a long bayonet-shaped organ, which 

 the animal during life has the power of locking in a fixed 

 position, so as to render it a very powerful weapon of 

 offence, and of again unlocking at its own will. When 

 fixed for striking it is supported in position by having a 

 strong cusp or tubercle on its dorsal surface brought into 

 contact with a curved process of the preceding segment. 

 QiypJiocrancfon rimajies, Spence Bate, was trawled in the 

 South Atlantic from a depth of 1,715 fathoms, and it is 

 noted as an instructive coincidence that in Willemocsia 

 lepfodadi/la, obtained in the same haul, the organs of 

 vision are reduced to a rudimentary condition, while in 

 Glyphoerangon they are unusually large. 



Nikoides, Paulson, 1875, is distinguished from Nika by 

 having an exopod on the first pair of feet, and by subdi- 

 vision of the fourth joint as well as of the fifth in. the 

 second pair. The type Nihoides Dance is from the Red Sea. 



Family 2 . — A Iplieidce. 



The rostrum is minute or of moderate size ; the eye- 

 stalks are short, and more or less covered by the projection 

 of the frontal margin of the carapace ; the mandibles have 

 a cutting edge distinct from the molar process, and a one- 

 or two-jointed ' palp ; ' the first pair of trunk-legs are 

 robustly chelate, sometimes unsymmetrical, the second pair 

 are long and slender, minutely chelate. 



Spence Bate makes a two-jointed mandibular ' palp ' 

 a character of the family, but in describing his own genus 

 Paralpheiis^ he says that it is uniarticulate, and in Alph&us, 

 Fabricius, ' three-jointed,' the latter being probably a slip 

 of the pen for two-jointed. Ten or more genera have 

 been assigned to the family, two of which occur on the 

 coasts of Great Britain. 



Alp>lteus^ FabriciuSj 1778, has a short pointed rostrum, 



