Guide to the Crustacea, Arachnida, Onychophora and Myriopoda exhibited in the Department of Zoology, British Museum (Natural History) .. . m ._.,-—*ii*;^ Fi.;. !pi^, from the Coal Jleasuras of Derbysliiif. 38 Guide to Crustacea. Table-case This division includes, among living Crustacea, a small numberNo. 5. Qf very peculiar forms recently discovered in the fresh waters ofTasmania and Victoria (Fig. 16). They are of special interest onaccount of the fact that they appear to be survivors of an ancientgioup of Crustacea of which the remains are found fossil in Car-bonife
Guide to the Crustacea, Arachnida, Onychophora and Myriopoda exhibited in the Department of Zoology, British Museum (Natural History) .. . m ._.,-—*ii*;^ Fi.;. !pi^, from the Coal Jleasuras of Derbysliiif. 38 Guide to Crustacea. Table-case This division includes, among living Crustacea, a small numberNo. 5. Qf very peculiar forms recently discovered in the fresh waters ofTasmania and Victoria (Fig. 16). They are of special interest onaccount of the fact that they appear to be survivors of an ancientgioup of Crustacea of which the remains are found fossil in Car-boniferous and Permian rocks. The drawing of the fossil Prac-anaspides praccursor (Fig. 17), exhibited in the case, shows thegreat resemblance in general form between that species and therecent Anaspides (Fig. 16). Division 3.—PERACARIDA. The carapace, when present, does not coalesce dorsally withmoie than four of the thoracic somites. The eggs and young are. Fig. 18. Mysis relicta, female, from the side, , Cervical groove ; vi., Brood-pouch. (From Lankesters Treatise on Zoology, after Sars.) carried in a brood-pouch formed by overlapping plates attached tothe bases of the thoracic limbs. The following Orders are included in this division:— Order 1. Mysidacea.,, 2. Cumacea.,, 3. Tanaidacea.,, 4. Isopoda.,, 5. Am]>liij)()d(i. Order 1.—Mysidacea. The general form is shrimp-like (Fig. 18). A carapace ispresent, but it leaves free at least live of the thoracic somites. Peracarida—Mysidacca, Cumacca. 39 There are Table-caseNo. 5. The eyes, when present, are stalked and movableswimming branches (exopodites) on the thoracic legs. Most of the Mysidacea live in the sea and many species arefound on the British coasts. Macromysis flexuosus is one of thecommonest species. A coloured drawing of the closely alliedLeptomysis is hung in Wall-case No. 5. A drawing of Arachno-mysis leuckarti in the Table-case gives an example of the remark-able
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectcrustacea, bookyear19
