| OCR Text |
Show 1900.] FROM THE FALKLAND ISLANDS. 545 In the second group we observe:- Carapace with postero-dorsal tooth E. schotti Ortmann. Uropods reaching apex I Eyes large E. gibboides Ortmann. of telson. { Eyes small E. pseudogibba Ortmann. Fifth and sixth pleon-segments with indentured hind margin E. spinifera Sars. Third pleon-segment with dorsal tooth strong E. mucronata Sars. First antenna; with basal leaflet acute, bifid E. gibba Sars. First antennae with basal leaflet rounded, simple E. vallentini, n. sp. EUPHAUSIA VALLENTINI, n. sp. (Plate XXXVII.) Bostral projection acute, short, not nearly reaching apex of eyes. Carapace with slight longitudinal elevation behind the rostrum ; a single tooth on lateral margin at about the middle. Third pleon-segment produced backward in a thin, almost spine-like, tooth of no great length, so as easily to escape notice. Fifth pleon-segment with postero-lateral corners rounded, not quadrate as figured by Sars in E. gibba. Sixth pleon-segment nearly as long as fourth plus fifth. The preanal spine tridentate, the lowest tooth much the largest. In one specimen out of four the upper teeth seemed to be represented only by a tubercle. The eyes are pear-shaped, of medium size. First antennae.-The first joint is longer than the second plus the third and has at the apex a smoothly rounded membranous leaflet, with a group of setae adjacent on the inner side, and on the outer a strongly projecting angle furnished with various plumose setae. The third joint has a small apical lobe on the underside and a membranous expansion along the upperside. Second antennae.-The scale extends well beyond the peduncle, the basal spine not nearly reaching the middle of the scale and only feebly pectinate on its inner margin. Mandibles.-Cutting-edge broad and thin, with two prominent teeth at the top, of which both are double in one mandible, but only the upper one in the other ; the molar prominent, its cylindrical crown radiated with finely pectinate teeth; palp strong, third joint about two-thirds of second, fringed on one margin with numerous spines, the second joint carrying setae. Lower lip.-The inner margin of each lobe with a fur of very short hairs extending nearly to the distal angle. First maxillae.-Unless by the greater breadth of the outer lobe, these maxillae are not easy to distinguish from those which have been figured for other species. Second maxillae.-The part which seems to vary most in tbe several species is the terminal joint or palp. It is here distinguished by its very considerable size, and by its shape, which is more that of a parallelogram, with obliquely truncate apex, than is shown in any other species for which these maxillae have been figured. Sars says of E. gibba that " the oral parts aud the legs would not seem to exhibit any essential difference from those of Euphausia gracilis." Third pleon-segment with dorsal tooth weak. |
