OCR Text |
Show 1901.] CRUSTACEAN FROM THE SOCDAN. 97 posteriorly, and the posterior margin is one-third longer than the length of this segment. The penultimate segment is just as long as the terminal, and trapezoidal; the anterior margin is in proportion to the posterior as 4 : 5, and the lateral margins are a little concave. The abdomen is smooth, punctate, especially near the anterior margin of the segments. The chelipedes (Plate X. fig. 1) are unequal, the right being the larger. The merus of the right chelipede extends but little beyond the lateral margin of the carapace. The upper margin is covered, except at the base, with transverse tubercular rugosities, and on the inner surface, close to and parallel with the smooth proximal part of the upper margin, is seen a row of six or seven small rounded tubercles that decrease in size anteriorly; this row reaches almost to the middle of the arm, and next to each of the first three tubercles there exists a much smaller tubercle. The anterior edge bears a double row of rounded tubercles; the internal row is formed by nine or ten that are not contiguous to one another; the external series bounding the anterior surface of the joint consists of about twice as many tubercles, but these are smaller, unequal, and contiguous to one another. About 2 millimetres from the anterior margin there is, on the anterior surface near the carpal articulation, a somewhat larger tubercle, with convex sides and rather a sharp poiut; around it several smaller granules are distributed, and a row of five or six larger ones extends from this tubercle to the lower margin of the arm. The lower margin bears along its whole length a row of fourteen or fifteen rounded smooth tubercles, that slightly increase in size distally and are somewhat larger than those of the anterior margin of the joint. The outer surface is finely punctate, but otherwise smooth. The carpus is a little tubercular along its internal margin, behind the acute, slightly depressed spine at the inner angle; beneath the latter there is another spine, only half as large and making a right angle with the larger. A little behind this smaller spine, on the lower border of the inner surface, there is a trace of a third in the form of a small blunt tubercle. The upper aud outer surface of the wrist is punctate and smooth. The larger hand (fig. 7) resembles that of P. hilgendorfi Hilgendorf (I. c. fig. 3). It is almost exactly as long as the cephalothorax is broad, and the fingers, that are somewhat less gaping than on the quoted figure 3, measure three-fifths of the whole length of the hand. The palm, near the articulation of the fingers, is about as high as it is long, measured horizontally; it is somewhat granular along the inner margin of its upper surface, but for the rest it appears smooth and shining; by means of a lens a fine punctuation is, however, observed, the punctures being disposed partly in longitudinal rows. The internal surface is also smooth, only a few granulations are seen close to and on its lower border, but these granulations i?re not visible when the hand is looked at from the outer side. The rather strongly compressed fingers are somewhat bent inward ; they are regularly tapering and eud in P R O C . ZOOL. Soc.^-1901, V O L . I. Xo. VII. 7 |