. Decapoda natantia of the coasts of Ireland. Decapoda (Crustacea). I. '08. 19 these on the completion of their metamorphosis descend to deeper water. Lo Bianco kept some young specimens alive in an aquarium, and found that they always swam head down- wards, as though endeavouring to reach greater depths. ? Amalopenaeus valens, Smith. ? Amalopenaeus valens, Smith, 1884, PI. x, tig. 2. ? Gennadas valens, Bouvier, 1908, PL i, fig. 3, PL ix, figs. 1-20. The principal characters of the solitary Irish specimen (a female, 48 mm. in length) are as follows : — 1. Eyes proportionally slightly larger th
. Decapoda natantia of the coasts of Ireland. Decapoda (Crustacea). I. '08. 19 these on the completion of their metamorphosis descend to deeper water. Lo Bianco kept some young specimens alive in an aquarium, and found that they always swam head down- wards, as though endeavouring to reach greater depths. ? Amalopenaeus valens, Smith. ? Amalopenaeus valens, Smith, 1884, PI. x, tig. 2. ? Gennadas valens, Bouvier, 1908, PL i, fig. 3, PL ix, figs. 1-20. The principal characters of the solitary Irish specimen (a female, 48 mm. in length) are as follows : — 1. Eyes proportionally slightly larger than in A. clegans. 2. Second joint of antennular peduncle, measured dorsally, fully three-quarters the length of the ultimate joint. 3. Apical spine of antennal scale extending beyond the lamellar portion. 4. Ultimate joint of mandibular palp four-fifths as long as the width of the first joint. 5. Anterior prominence of merus of second maxillipede slightly less than one-third the total length of the joint. Chela of second pereiopod slightly shorter than carpus. Merus of third pereiopod very evidently shorter than carpus. Thelycum as in text figure ; its principal features being a single large plate, almost round, between the fifth pair of pereiopods, and a pair of triangular plates furnished with a few stiff setae at the base of the fourth Amalopenaeus valens (.?), Thelycum. The branchial formula is the same as in A. elegans. The colouring is also much the same as in that species; the deep blue pigment has almost exactly the same distribution,^ but the black spot on the dorsal aspect of the eyestalk behind the cornea is almost obsolete. 1 Neither this specimen nor numerous examples of A. elegans (examined when freshly caught) showed such large areas of dark blue pigment on the abdomen as are depicted by Bouvier for valens (1908, PL I, fig. 3); otherwise this coloured illustration gives an excellent idea of the appearance of Irish sp»cimens of this genus. B 2. Please no
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectdecapod, bookyear1910
