128 MEMOIRS OF THE NATIONAL ACADEMY OP SCIENCES. 



Explanation of Plate II. 



Fig. 1. Acanthotelson etinipsoni M. «& W. 



Fig. 2. Acanlhottlson slimpsoiii M. & W., reverse of lig. 1. 



Fig. 3. Acanthotelson stimpsoni M. & W. 



Fig. 4. Acanthotelson ? mayister Pack. 



Fig. 5. Acanthotelson ? magister Pack., reverse of fig. 4. 



From pbotographs taken by Mr. Eobert L. P. Mason. 



Note on an additional specimen. — Since this memoir was sent to the printer I have received a larger speeimeu from 

 Mr. Lacoe, labelled " Braidwood, 111., Q'", whicL, exclusive of the antenna; and telson, measures about 82"'™. There 

 are traces of four pairs of thoracic feet which are long and slender and bent backwards from the head, reminding us 

 of the four hinder legs of an ordinary shrimp seen from one side. There are traces of the antennae, better preserved 

 than in the original specimen. There appear to be a pair of large auteunie, the scape composed of three large joints, 

 the second and third smaller and together equalling in length the basal joint; these antenna appear each to bear a 

 large antennal scale, resembling those of the Macrura, and reaching as far as the middle of the third autennal joint. 

 The characters shown by this specimen lead me to refer it to a genus distinct from Acanthotelson, for which the 

 the name Belotelson (the entire name, Belotelson magister) is proposed. Additional siaecimeus are much desired to 

 complete our knowledge of its affinities. 



