OCR Text |
Show 82 CRUSTACEA. tatory. The lateral antenn~ have a scale at their base, and the stem of the intermediaries is composed of three filaments. The body is narrow and ~longated; the ocular pedicles are always short. This family is composed of but one genus, that of SQUILLA, Fab., Which we will divide in the following manner: In some the crustaceous shield is preceded by a small and more or less triangular plate, situated above the segment in which the eyes and mediate antenn::e are inserted, only covers the anterior portion of the thorax, and does not curve downwards on the sides. The piece which serves as a peduncle to the mediate antenn::e, as wellas the ocular pedicles and the external sides of the end of the abdomen, are exposed. Here the body is almost semi-cylindrical, the posterior edge of the last segment being rounded, dentated or spinous; the lateral appendages of the last six feet are styliform. SQUILLA, Lat. The true Squill::e, along the whole inner side of the penultimate segment of the two large claws, have an extremely narrow groove, dentated on one of its edges and spinous on the other, and the ensuing joint or the claw, falciform and usually dentated. Squilla mantis; Cancer mantis, L.; Herbst., XXXIII, 1; En· cyclop. Method., Atl. d'Hist. Nat., CCCXXIV; Desmar., Consid., XLI, 2, is about seven inches in length. The base of the large forceps is furnished with three movable spines, and its claws have six elongated and sharp-edged teeth, the last one being the largest. The segments of the body, the last one excepted, are marked by six longitudinal ridges, mostly terminating in a sharp point; the middle of the last is strongly cal'i· nated, punctured and terminated posteriorly by a double range of indentations, and four very stout points, the mediate teeth of which are most closely approximated; each lateral margin has two reflected or thicker divisions, the last one terminating in a point. The peduncle 'of the lateral fins is prolonged beneath and terminated by two very strong teeth. It is common in the Mediterranean. The Squille de Desmarest, Hisso, Crust. II, s, which also inhabits the same sea, is but two inches and a half in length. Its claws have five teeth; the shell and the middle por· STOMAPODA. 83 abdominal sef)'ments, the last ones excepted, are tion of the ~ smooth(l). In the GoNoDAOTYLUs, Lat., The groove of the penultimate segm~nt of the l~rge claws i~ wi-d 't extremity presenting ne1ther dentat10ns nor spmes. dene at 1 s ' . . fi · dilated or resembles a knot near its base, termmatmg The nger lS ' Th 11 in a straight or slightly curved compressed point. ey are a foreign to Europe(2). There, the body is extremely narrow and depress~d, and the. last ent almost square, entire, and without dentations or spmes. ~~;lateral appendage of its last six feet is in the form of an almost orbicular and slightly bordered palette; the antenn::e and feet are I ter than in the preceding; the penultimate segment of the large s 10 clawr s has its inner margin fringed with numerous c1T 1 a m· th e t o rm of little spines; the finger is falciform. CoRONis, Latr. But a single species is known(3). . In the remaining Stomapoda of this family the sh~ll 1s almost membranous and diaphanous, covers the wbol.e thorax, ~s curved laterally beneath, prolonged anteriorly into a spme or ens1form blade, and projects above the base of the mediat~ antenn::e and of the eyes. This base or support is susceptible of bemg. curve~ under and enclosed in the case formed by the curvature of the sh1eld. The pos-terior fins are concealed under the last segment. . These very small, soft Crustacea are peculiar to the Atlantic Ocean and the Eastern seas. The fingers of the large claws have no teeth; the second joint of the ocular pedicles is much larger than the first, and has the figure of a reversed cone; the eyes properly so called are large and almost globular; the fin-like ~ppendage of the feet resembles that of the Squill::e and Gonodactyh. In the ERICHTHus, Latr.-Smerdis, Leach, The first joint of the ocular pediclcs is much shorter than the second· the middle of the lateral edges of the shield has a strongly ' (1) For the other species, see the ::Lrticle Sq uille, and p.l.' of the Encyc. Method.; Desmar., Consid. In pl. XLII, he bas given a deta1led figure of the Squille queue-rude. F b (2) >oJ qu·z lla scyll a ru.~, Fab.; Rump 11 ., ."...1 ( us. • III' F ·' -'~ quilla chira0m·a, ' a ·; .' 'tho Desmar. Consid., XLIII. Sec the article Squille, of the Bncyclopedta Me • dique. (3) See Encyclop. Method., art. Squill c.. Squilla rosebia.'l Risso. |