OCR Text |
Show 96 DR. .1. G. DE MAN UN A NEW FRESHWATER [Feb. 19, of the orbits and the granulated tooth between the extraorbital and epibranchial angles are covered and concealed by it. The furrow between the postfrontal crest and the upper margin of the orbits is very concave and deep (Plate X. fig. 2). The whole upper surface of the carapace is smooth and shining, and presents, under an ordinary lens, a very fine punctuation, but is nowhere granulated. The orbits (fig. 2) are large, their width measures three-fourths of the free border of the front, and they are one and a half times as broad as high. In a front view of the carapace (fig. 2), the somewhat concave external portion of the upper margin of the orbits runs obliquely downwards; whereas the lower margin, which is somewhat punctate but otherwise smooth, has a transverse direction, being but very little arcuate ; the lower margin of the orbits shows a deep notch or hiatus just below the extraorbital tooth. The superior margin of the orbits and the free edge of the front are also smooth. The suborbital area is separated by an arcuate, rather deep sulcus from the subbranchial region; the posterior margin of this groove is granulate or crenate, presenting about twenty rather small crenulations ; there are three or four granules on the suborbital area close to the groove that separates it from the branchio-stegite, but for the rest this region and the branchial floor also are smooth. The branchiostegite bears a few smooth, rounded granules on its anterior extremity (fig. 2), and the suture that separates it from the subhepatic and subbranchial regions is bordered by a row of granules that gradually grow smaller from before backwards ; its anterior part is rather deep. The epistome is smooth. The median triangular process of its posterior border is large aud salient, and its lateral margins have seven or eight coarse granules on each side; the slightly concave external portions of the posterior border of the epistome are smooth and rather sharp, but the median process bears also a few granules on its surface. For the rest the epistome, the basal plate, and the basal joints of the outer autennae are smooth. The ischium of the external maxillipede (fig. 4) is smooth, rather coarsely punctate, and has a deep furrow that does not reach to, the anterior margin of this joint but ends just behind it; it runs distinctly somewhat closer to the internal than to the external margin, and almost parallel with the former; the merus-joint is also smooth and finely punctate, though somewhat more coarsely on the thickened posterior margin. The sternum shows a fine, not close punctuation, but is for the rest smooth; quite anteriorly a transverse groove unites the poslero-external angles of the ischium-joints of the outer foot-jaws with one another. Along the insertion of the chelipedes the lateral margin of the sternum is thickened or raised, just as in P. infravallatum Hilg. (Hilgendorf, I. c. fig. 2 a). The male abdomen (fig. 6) resembles that of P. suprasidcatum Hilgendorf (I. c. fig. 5 a). The terminal segment is triangular with obtuse extremity ; the lateral margins are somewhat concave |