CANCROIDEA. 



PANOP^EUS CRENATUS (Edwards and Lucas) . 

 Callao, Peru. 



Length of carapax of a male, ten and a half lines; greatest breadth, 

 fifteen lines. The regions are very indistinct, yet the outline of the 

 medial may be made out; it is somewhat narrower than a line con- 

 necting the outer orbital angles. 1 M is slightly apparent and so also 

 2 F. Very faintly also, 5 L and 6 L may be distinguished through a 

 slight bending of the surface. The four teeth into which the thin 

 margin is divided by slight incisions, represent all the normal teeth 

 excepting the second (E), which is coalesced with the first or orbital. 

 The tooth S is subacute, and the outline of the carapax declines back- 

 ward in an oblique and nearly straight line directly from the summit 

 of the tooth. 



One female, with eggs under the abdomen, was only six lines in 

 length. 



P. crenatus, M. EDWARDS and H. LUCAS, Crust., D'Orbigny's S. A., 16, pi. 8, f. 1. 



GENUS MED^EtfS, Dana. 



Carapax anyustus, paulo transversus. Orbitce margo inferior externus- 

 que dentibus tribus iitstructus. Frons sat brevis. Margo carapacis 

 antero-lateralis sub orbita productus. Articulus antennae externce 

 Imus uti in Xantho. Abdomen marls 5-articulatum, segmento ultimo 

 bred. Pedes antici crassi. 



Carapax narrow, somewhat transverse. Outer and lower margin of 

 orbit formed of three teeth. Front rather short. Antero-lateral 

 margin of carapax extending far below the line of the orbit. First 

 joint of outer antennae as in Xantho. Abdomen of male five-jointed, 

 last segment short. Anterior feet stout. 



This genus is very near Xantho, the characters of the orbit, its 

 very narrow form, and the fact that the lateral margin instead of 

 extending towards the orbit takes a course much below it, being the 



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