. Geological magazine. Cyclus Johnsoni, H. Woodw., and counterpart of a specimen from the Pennystone Ironstone band ofthe Coal-measures, Coseley, near Dudley. Dra^mi twice nat. size, a, a, antenna^ ^b, endopodite (?) of one of mouth-organs ; c, c, appendages of the posteriorsegment of the body. (Original specimen in Biimiagham University Museum.) seven or eight pairs of simple limbs are seen, corresponding willia similar number of cephalic somites, partially united dorsally,the thoracico-abdominal segments and the short telson not behigdeveloped until a much later stage. This e

---

. Geological magazine. Cyclus Johnsoni, H. Woodw., and counterpart of a specimen from the Pennystone Ironstone band ofthe Coal-measures, Coseley, near Dudley. Dra^mi twice nat. size, a, a, antenna^ ^b, endopodite (?) of one of mouth-organs ; c, c, appendages of the posteriorsegment of the body. (Original specimen in Biimiagham University Museum.) seven or eight pairs of simple limbs are seen, corresponding willia similar number of cephalic somites, partially united dorsally,the thoracico-abdominal segments and the short telson not behigdeveloped until a much later stage. This early or premature hatching out of the young characterisesthe Phyllopoda, and indeed most living Entomostraca. In thoseTrilobites whose early history is known the young, as in Sao,Ptychoparia, TriartTirus, Proetiis, Acidaspis, and Dahnanites, ar&almost as simple, or even more so, in their earliest known stagesas Cyclus (see Beecher and Barrandes figures infra, p. 492). It must, of course, be borne in mind that this

---

Size: 1509px × 1655px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: ., bookcentury1800, bookdecade1860, booksubjectgeology, bookyear1864