1897.] NATURAL SCIENCES OF PHILADELPHIA. 391 



Key to Species Examined. 



a Abdomen emarginate or notched at the distal end. 



b Two spines or tubercles overhanging the frontal notch. 



c Spines united near the base. pallida 



c' Tubercles free at the base. erosa 



b' No spines or tubercles overhanging the frontal notch. 



c With a low ridge arising between the eyes and interrupted 

 on the median line. 



d Outlines of abdomen subparallel. nebulosa 



d' Outlines strongly arcuate. angulata 



c' Without a ridge between the eyes. 



d Outline of abdomen subtriangular. 



e Front not excavated. * consolidata 



e' Front excavated. 



f Outlines of thorax subparallel. marmorata 

 f Outlines of thorax strongly arcuate. 



bicuspida 

 d' Outlines of abdomen rounded. 



e Length of abdomen equal to width at base. 



laticauda 

 e' Length of abdomen equal to one and one-half 

 times the width at base. harfordi 



a' Abdomen pointed. 



b Undulations of the body not tubercular or spiny. 



c Tubercle in front of the eyes not margined. nodulosa 



c' Tubercle on the frontal margin and forming a part of it. 



Icevis 

 b' Undulations of the body tubercular and spiny. 



c Four spines on the front of the head; body spinous. 



m uricata 



c' A wedge-shaped tubercle behind the frontal notch ; body 



tubercular. picta 



Synidotea bicuspida (Owen). Fig. 1. 



Idotea bicuspida Owen, Crustacea of the ' Blossom,' p. 92, pi. xxvii, fig. 6, 

 1839. 



Idotea pulchra Lockington, Proc. Cali- Acad. Sci., VII. p. 44, 1877. 



Edotia bicuspida Miers, Journal of the Linnean Society of London, XVI, 

 p. 66, 1883 (pars). 



Synidotea bicuspida Sars, Crustacea, Norwegian North Atlantic Exped , p. 

 116, pi. X, figs. 24-26, 1885; equal to Synidotea incisa Sars, Crustacea et 

 Pycnogonida nova, etc., No. 8. 



