C PEOCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1896, 



legs are chelate, the second being the longest pair ; the carapace is 

 even and rounded, with two points, the one above, the other 

 beneath the peduncle of the external antennas ; the rostrum is of 

 great length, curved upwards, and armed with 7 or 8 teeth above 

 and 4 or 5 beneath ; the inner antennas have three filaments, two of 

 which are long ; the outer antennas have filaments of very great 

 length, and a long and pointed scale near the base. The oldest of 

 this type known is the JEger raiblana from the Trias of Eaibl, 

 Austria. Two species of JEger, namely, JE. Marderi and 2E. Brodiei, 

 have been described by me from the Lower Lias of Lyme and of 

 "Warwickshire ; five forms of the same genus have been figured by 

 Miinster and Oppel from Solenhofen, remarkable for the length of 

 the rostrum and of their last pair of spinose pediform maxillipeds. 

 The genera Udora, Hefriga, and Elder, from the Lithographic stone, 

 probably all belong here. 



Another Prawn, OpIopJiorus van-der-MarcJci, Schliiter, is from 

 the Chalk of Westphalia ; two species of the genus Homelys (a 

 freshwater Prawn) are from the Miocene of (Eningen ; Micropsdlis 

 papyracea, H. v. Me}^er, from the Tertiary Paper- coal of Rott, near 

 Bonn, and Palcemon exul, Pritsch, from the Tertiary of Bohemia, 

 complete this tribe. 



Polycaeplnea. — This section embraces the families Nikidas, 

 Alphasidas, Hippolytidas, and Pandalidas. All the members of 

 this group are distinguished by one common character : it is, that 

 the second pair of slender thoracic legs have the carpus, or fifth 

 joint, multi articulate — that is, subdivided into a greater or less 

 number of minor joints, like the nagellum of the lobster's antenna. 

 It is interesting to record that this remarkable and multiversatile 

 hand had already been in use, no doubt prior to the Upper Jurassic 

 period, for the genus Blaculla had jusb such slender limbs of this 

 pattern, one fourth longer than its entire body. Three species have 

 been noticed by Oppel from the Lithographic Stone of Solenhofen in 

 Bavaria ; while 27 genera of world-wide distribution still illustrate 

 the convenience of this form of limb, which may serve to assist this 

 small Shrimp to extract, from spiral shells and slender worm-tubes, 

 food of a nutritious and appetizing kind. 



Ceangonidea. — In Crangon the rostrum is absent or rudimentary ; 

 the inner antennas have a dilated base terminating in two filaments ; 

 the external antennas are nearly on the same line with the inner 

 ones, and have a large scale at the base ; the first pair of thoracic 

 legs is subchelate ; and the finger is inflected to meet a small 



