Year: 1868
Type: book
Abstract: Mandibles distinct, mostly strongly toothed at the lower extremity palp of moderate size, and bearing a more or less developed bi-anchial appendage.First pair of maxillae bearing a large branchial plate.Feet one branch rudimentary, immobile ; the other elongated, cylindrical, flexible, many-jointed, armed with long natatory setae, arranged in a single series ; basal portion very large and stout, filled with muscular bands. Upper antennae scarcely natatory.Mandibular palp very large, genicu- late, subpediform, destitute of a branchial appendage.First pair of jaws without a branchial plate.Post- abdomen divided into two broad plates, which are imguiferous behind.Feet two pairs, the last bent up within the"] valves.Postabdomen forming two elon-[ Qypridje gated narrow rami, wliicli are usually clawed at the apex.[>three pairs, all ambulatory, much alike in structure, and directed forwards.Postabdomen rudimentary, forming two veiy !> small lobes.Antennae very little adapted for swimming.PODOCOPA.Cythe-''one pair only, of singular shape, forming"| an elongated, curved, flexible, annulated, vermiform appendage, which is spiniferous towards the apex.Upper antennte large, distinctly jointed, geniculate at the base.Cypeidi Mandibles proper obsolete.Second pair of jaws bearing a large branchial plate.E3'es compound, pedunculated, widely separated ; between the two in front a large simple eye and a short fi'ontal tentacle.J two pairs, the posterior very small and" rudimentary; the anterior provided, like the second pair of jaws, with a small, lobed branchial plate.Upper antennte of Conchcethe female small and weak, immobile and indistinctly jointed.Mandibles distinct.No eyes.Frontal tentacle very large, and .MYODUCOPA.mostly dilated at the apex.both branches well developed, moveable, and natatory.Upper antennae also"] natatory, not geniculate, ending iu a lash of long setfe.Mandibles distinct, palp | short and scarcely pediform, provided with a small branchial appendage.Two [ pairs only of thoracic appendages ; the anterior large, bifid, natatory ; the poste-( rior membranaceous and branchial.Eyes wanting.Postabdomen divided into | two short laminae, spinous behind.J flattened, similar to the feet of the Copepoda, basal portion biarticidate and geniculate; branches flattened, composed of few joints, and bearing numerous setae on both margins.Upper antennEe very large and strong, many-jointed, geniculate at the base, shortly spiniferous.Mandibles small and weak, palp large.Three pairs only of thoracic appendages, all maxilliform.Palp of the mandible J> and first jaw bearing internally a comb of large setas.First and second pairs of jaws provided with a large branchial plate; third pair rudimentary in the female, in the male well developed and prehensile, Postabdominal rami small and nan'ow, distinctly separated, and spiniferous at the apex.POLYCO-CLADOCOPA.Cythe-( PLATYCOPA.EELLID^J.Section I. PODOCOPA.Pam. 1. CypRiDiE, Valves mostly thin and smooth, more or less sinuated below.Upper antenna?mostly seven-jointed, and beset with numerous setse, which form a dense brush of greater or less length; lower antennse geniculate and bent backwards, fouror five-jointed, armed at the distal extremity with from three to five long, slightly curved claws, and bearing commonly on the posterior aspect of the antepenultimate joint a bundle of setse.Mandibles powerful, and divided at the extremity into several teeth, bearing a large four-jointed palp, the first joint of which is provided with a branchial appendage.Two pairs of jaws : the first large, and divided into four digital segments, the anterior segment being larger than the rest, two-jointed and giving attachment to a large branchial plate Monoculus aurantius, Jurine, Hist, des Monocles, p. 173, pi.xviii.figs.5-12.ruber, Idem, ibidem, p. 172, pi.xviii.figs.3, 4.Valves oblong, subreniform, narrowed in front.Anterior extremity narrow, bordered by a flattened encircling lamina ; posterior broad and well rounded.The ventral margin is straight or slightly sinuated ; the dorsal arched, highest at its posterior third.Seen from above, the carapace is oblong, ovate, tapering to the anterior extremity, which is acutely pointed, the right valve being considerably overlapped by the left.Tront view ovate, the suddenly compressed anterior margins projecting sharply forward.The surface is indistinctly granular, and finely punctate.Colour ochreous yellow, marked with bands and blotches of deeper orange.Near the anterior third of the dorsum there is frequently a conspicuous deep-brown or black spot, marking probably the position of the eye.The arrangement of the antennal setas is precisely like that of C. virens,-the upper antenna bearing nine long and several shorter plumose filaments ; the lower five, which reach but slightly beyond the apices of the claws.Eour much shorter and mostly non-plumose setae rise from the middle of the fourth joint, and reach not very much beyond the bases of the claws.These are found in all members of the genus.Setae of the abdominal rami four, the two shorter ones being much longer than those of C. fusca or 0. virens.The anterior portion of the shell is not unfrequently studded with a number of minute tubercles, which along the margin are gathered into a regular row of from twenty to thirty (fig.21), producing an appearance as of a finely crenated or serrated border.The marginal row of tubercles is present, however, only on the right or smaller valve, which is provided internally with a narrow laminar plate (fig.22), and is received within the overlapping and perfectly simple margin of the left valve.The pos- terior margin is also occasionally, but less frequently, tuberculated in a similar manner.Length i^i-j height g^j-in./.K.s-i C. incongruens seems to be one of the less common species of this genus.It has been found in Kent and Essex by Professor T. Rupert Jones, at Blackheath, Windsor, and Dover by Dr. Baird, in the island of C umbrae and in a lagoon on the Ayrshire coast by Mr. D. llobertson, in the county of Durham and in the Isle of Arranmore (Galway) by myself.It has a wide range on the continent, being mentioned by various authors as occurring in Switzerland, Germany, Norway, and Sweden.My figures and description of this species were completed before I became acquainted with the memoir of Pischer contained in the ' Transactions of the Munich Academy ; and it is satisfactory to find that the observations of that author as to the distinctive characters of C. aurantia are quite in unison with my own.Dr. Pischer, however, assigns a specific rank to C. rubra, Jurine, almost entirely on the ground of the want of tuberculation of the carapace, at the same time admitting that the subject wants investi- gation, and that the relations between C. fusca, C. aurantia, and C. rubra are far from being clearly made out *. Prom what has been said above, it will be seen that I regard the two former species as distinct, not only from characters afforded by the carapace, but * Es muss iibrigens erst weitere Beobachtung lehren, ob nicht Uebergangsformen zwischen C. aurantia, fusca und rubra stattfinden, und sie alle drei nur als eine Species zu betrachten sind, da ihr Korperbau durchaus keine weseut- Uche Verschiedenheit wahrnehmen lasst." 3 D 2 however, this term has no applicability; and I have therefore adopted Mr. Norman's specific name.7. Cypris bispinosa, Lucas.(Plate XXYI.figs.14-17.)Cypris bispinosa, Lucas, Explorat.Scient.d'Algerie, Animal.Artie.Crustac.t.viii.figs.7,7 a, b [fide Baird).Carapace oblong, subpyramidal, very tumid on the ventral surface, and gradually narrowing towards the dorsum.The ventral margin is elevated into a broadly rounded ridge which runs backwards, becoming gradually narrower and more sharply defined, until it ends, considerably behind the middle of the valve, in a sharp, curved, projecting spine : anteriorly the ridge curves upwards, and is gradually lost on the surface of the shell.The anterior margin is narrow and rounded.Dorsal margin arched, highest a little in front of the middle, where it is angular or gibbous, sloping equally to each extremity.The posterior extremity forms a slightly produced beak a little below the median line of the valve, thence sloping steeply upwards to the dorsal, and curving gently downwards to the ventral margin.Seen from above, the outline is tumid, oval, with acutely pointed extremities, the anterior of which is produced so as to form an " ogee " outline ; the lateral spines are very conspicuous both in the dorsal and ventral aspects.End view triangular, base flattened, sides convex, lateral angles produced and rounded.Surface smooth, very finely punctate.Colour light green.Length ^in., height ys" in-Por specimens of this noble species (the finest British Cypris) I am indebted to the Rev. A. M. Norman, to whom it was forwarded some years ago by Dr. Lukis of Guern- sey, who took it in a freshwater pool in that island.Dr. Baird identifies the specimens with Cypris bispinosa, Lucas, which was found in Algeria " in a little streamlet of fresh water flowing from the Boudigma."8. Cypris gibbosa, Baird.Cypris gibbosa, Baird, Mag.Zool.& Bot.i. p. 137, t. v. fig.15, 1837; and Nat.Hist.Brit.Entom.p. 156, t. xix.fig.8. " Shell ovate, and much elevated on the upper margin, the centre exhibiting a large gibbosity or hump ; sinuated underneath.The valves are smooth, except round the edges, which are beset with short fine hairs, are nearly opaque, and of a light green colour, the anterior extremity being paler than the other parts of the shell, filaments of both pairs of antennae beautifully plumose." Hab.Ditch near tlie Surrey Zoological Gardens, June 1836."I know nothing of C. gibbosa, except from Dr. Baird's description.9. Cypris tessellata, Pischer.(Plate XXIII.figs.39-45.)
Author: George Stewardson Brady
Language: English
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: gold
OpenAlex ID: W2103780963