. Annual report. 1st-12th, 1867-1878. Geology. 404 GEOLOGICAL SUEVEY OF THE TEEKITORIES. Areliicerebrum i ^exSmat Merostomata (Liraul us). The syncerebrum of the Tetradecapoda (Amphipoda and Isopoda), judging by Leydig's figures1 and our own observations (from dissections made by Mr. J. S. Kingsley) on that of Idotsea and Serolis2, is built on a different plan from that of the Decapoda. The syncerebrum of the Phyllocarida is somewhat like that of the Cladocera and Copepoda (Cal- anidse); being essentially different from that of the majority of the Malacostracous Crustacea. The Copepodous synce
. Annual report. 1st-12th, 1867-1878. Geology. 404 GEOLOGICAL SUEVEY OF THE TEEKITORIES. Areliicerebrum i ^exSmat Merostomata (Liraul us). The syncerebrum of the Tetradecapoda (Amphipoda and Isopoda), judging by Leydig's figures1 and our own observations (from dissections made by Mr. J. S. Kingsley) on that of Idotsea and Serolis2, is built on a different plan from that of the Decapoda. The syncerebrum of the Phyllocarida is somewhat like that of the Cladocera and Copepoda (Cal- anidse); being essentially different from that of the majority of the Malacostracous Crustacea. The Copepodous syncerebrum is an unstable, highly variable organ, but on the whole belongs to a different category from the syncerebrum of other JSTeocarida. We have tben, probably, three types of syncerebra and two types of archicerebra among existing Crustacea. HOMOLOGIES OF THE CRUSTACEAN LIMB. Comparison with limbs of Cladocera.—We should naturally first com- pare the appendages of the Phyllopods with the members of their own. Fig. 27.—First leg of male of Moina (for comparison with that of male Limnetis): ex, exite; epip, epipoilal portion of limb; en4-en6, endites 4-6, to compare -with the endites forming the hand of the male Limnetis. The base of the endopodal region (en 1-3) not diiferentiated as in the l'hyllopod limb. order, and especially the Cladocera; and here, whether we consider the carapace-valves, the eyes single and compound, the two pairs of antennae, or the telson, we find a very close connection in form between Limnetis and Daphnia or Moina. In the accompanying figure from Grube's and Weismann's excellent paper on the Daphnidae3 (which we have slightly modified, introducing dots in the branchial portion) may be seen how nearly the first leg of the male of Moina rectirostris agrees with that of the male Limnetis, as seen in the sixth endite forming a claw like that of Limnetis, although the flabellum is not clearly dif- 1 Tafeln zur Vergleichenden Anatomie. Von F. Leydig. T
Size: 1902px × 1314px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1860, bookpublishe, booksubjectgeology
