Guide to the Crustacea, Arachnida, Onychophora and Myriopoda exhibited in the Department of Zoology, British Museum (Natural History) .. . of the sub-class, some specimens being evenlarger than that exhibited here. The order Branchiura includes a small number of fish-parasites whose exact relations to the other Copepods are possess a pair of compound eyes, and a piercing stylet, con-nected with a poison-gland, in front of the mouth. ArgvJuafoliaccvs is common on fresh-water fishes in this country. Thelarge Argnlim scutiformis is taken from marine fishes in Japan. Cirripedia. 31 Su
Guide to the Crustacea, Arachnida, Onychophora and Myriopoda exhibited in the Department of Zoology, British Museum (Natural History) .. . of the sub-class, some specimens being evenlarger than that exhibited here. The order Branchiura includes a small number of fish-parasites whose exact relations to the other Copepods are possess a pair of compound eyes, and a piercing stylet, con-nected with a poison-gland, in front of the mouth. ArgvJuafoliaccvs is common on fresh-water fishes in this country. Thelarge Argnlim scutiformis is taken from marine fishes in Japan. Cirripedia. 31 Sub-class CIRRIPEDIA. The members of this group are sedentary animals, attached by Table-the anterior part of the head-region, and having the body generally ^os_^3& by a fleshy mantle, representing the carapace, strength-ened externally by shelly plates. There are typically six pairs oftrunk-limbs, each two-branched and many-jointed. On account of their shelly covering the Cirripedia were classedby the older naturalists with the Mollusca, and it was only whentheir larval stages were discovered in 1829 by J. Vaughan. Fig. VI. Group of specimens of a stalked Barnacle (Lepas aiiatifera). One showingthe cirri extended as in life. [Table-case No. Thompson, that their affinities with other Crustacea were recog-nised. Nearly all the Cirripedia are hermaphrodite, having bothsexes combined in each individual, a condition very rare among theArthropoda. In some cases, however, there are dwarf maleindividuals which pair either with females or with hermaphroditesof normal structure. The Sub-class may be divided into five Orders, but three ofthese comprise only a few imperfectly-known forms which cannotbe exhibited here. 32 Guide to Crustacea. Table-caseNo. 3. Order 1.—Thoracica. This Order includes the typical Cirripedes, in which the sixpairs of feathery trunk-limbs are well developed. Two sub-ordersare recognised. In the sub-order Pedunculata (the Stalked Barnacles) the
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectcrustacea, bookyear19
