724 PROCEEDINCS OF THE NATIONAL MUSEUM. vou xxv. 



Appendages and vental surface yellowish brown, deeper at the 

 center; endopodites and exopodites glass-green. 



Length 18 mm.; length of carapace 18 mm.; breadth of carapace 

 10 mm. ; length of abdomen 6 mm. ; breadth 6 mm. Male about 

 one-third smaller, with only the regular peg and semen vesicle for 

 copulatory organs. 



Ilahltat. — Mediterranean iit Nice on Caranx luna Geoflf roy, by Risso, 

 and on Pugellus erythrhius Linnaeus, by Thorell. The specimens 

 found ])y Risso were usually attached to the base of the pectoral fin, 

 and the single specimen found by Thorell was similarly placed. 



All Risso's specimens were males, while ThorelFs was fortunatel}^ a 

 female. The latter seems to think that this species might be regarded 

 as the type of a new genus for which he would propose the name 

 Agenor Risso. But the only reasons for this which he can bring for- 

 ward are tlie unusual development of the carapace, the absence of 

 tlagella, the presence of two lamella; on the last thoracic segment, and 

 certain slight moditications in the mouth parts. It is ver}^ evident 

 that none of these have any generic value. 



The shape and markings of A. giganteus^ as given in the figure by 

 Lucas (1845) are almost exactly the same as those of the present species 

 as figured l>y Thorell. The color also (yellow finely dotted and trav- 

 ersed lengthwise on either side with a red-brown line) is what might 

 fairly be expected in a dried specimen, the only one ever obtained. 

 And then this single specimen was found near Algeria, in the Medi- 

 terranean, which is not so very far from Nice. For these reasons and 

 because the specimen was dried, and neither adequately described nor 

 figured it seems best to consider it another specimen of A. jyurjmi'eus 

 until some better data can be obtained. 



{purpureus='^\\Y\AQ., from the color). 



ARGULUS COREGONI Thorell. 

 Plate XXIV, figs. 70, 71. 

 ArgiUufi coregoni Thorell, 1864. 



Carapace orbicular, a little longer than wide in the female, a little 

 widei- than long in the male; posterior sinus about one-third the length 

 of the carapace, as wide as long in the female, narrower in the male 

 and converging so that the tips of the lobes overlap. Abdomen long, 

 elliptical, two-fifths the length of the rest of the body, cut fully to 

 the center with lanceolate-acuminate lobes; papillae basal. 



Sucking disks small, one-sixth the width of the carapace and rather 

 widely separated; posterior maxillipeds large, well armed; basal plate 

 rectangular, teeth stout and sharp. 



Antenna? medium size and well armed. Swimming legs reaching 

 l)eyond the carapace in the female, entirely covered in the male; lobes 

 on the posterior pair very small and well rounded. 



