The Early Development of a Polyclad: Planocera Inquilina Wh, Volume 591907 - Embryology - 46 pages |
Common terms and phrases
abdomen anal annelids antennæ apex apical arcuate August 16 Baboquivari Mountains bands base blastoderm blastopore brown Bruner canal carina Carr Canyon caudal femora caudal margin caudal tibiæ Cedar Keys cells cephalic cerci ciliated cleavage color commissure conklini Crepidula cytoplasm diameter Dinophilus disk distal distinctly dorsal ectoderm elytra eyes F. H. Snow fastigium female femur Fulgur Gainesville ganglia ganglion genus Giglio-Tos glands greatest width head Huachuca Mountains hypodermis laterad lateral line lateral lobes Length of body Length of caudal Length of pronotum Length of tegmen longitudinal macromeres male median mesonotum muscles narrow nephridia nephridium nuclei ovipositor Pablo Beach pair pale petrosa Phila pine woods portion posterior Proc pronotum prostomium proximal Pyrula quartet rounded Sapucay Saussure Scudder setæ shell side slender slightly smooth stage species specimens spines Stål subgenital plate surface tegmina tibiæ transverse U. S. Nat ventral whorl wings yolk Zool
Popular passages
Page 513 - "Up to a late stage in the spiral period (twentyeight cells) every individual blastomere and every cell division is represented by a corresponding blastomere and a corresponding cell division in the embryo of the polyclad and in that of the gasteropod."
Page 546 - (p. 13) says: "If we accept Lang's view, which is supported by a large amount of evidence, that the platodes are not very far removed from the ancestral prototype of annelids and mollusks, we should expect to find in the
Page 513 - gives rise to the entire ectoblast, the second and third groups to the mesoblast, the macromeres to the entoblast. In the mollusk and annelid, on the other hand, the second and third groups of micromeres give rise to the ectoblast, like the first set, and the
Page 236 - petrosa by its large and swollen apex; by its smooth stage which occupies little more than one whorl ; by its more or less suppressed curved rib stage, and by the earlier decline of the spirals immediately below the shoulder. The following table will serve to compare
Page 239 - Athleta clayi is almost identical with the examples of A. petrosa main stock in everything except its smooth stage. In its smooth stage it approaches Athleta sayana of the later Claiborne beds of Alabama. We are reasonably safe in concluding that A. sayana, was derived from
Page 230 - In their case, thanks to the work of Prof. Eugene A. Smith and Mr. Lawrence C. Johnson," it is possible to arrange the races in chronologic order. In the present study the races discussed are mostly from the Eocene beds west of the Mississippi River, and unfortunately the deposition of callus never became normal and regular, though in Europe
Page 219 - of about 2 whorls. Greatest diameter — 2.8 mm. Fig. 8.—Apex of Pyrula dussumieri Valenc. Recent. China. Smooth stage of about 1.6 whorls. Greatest diameter = 3 mm. Fig. 9.—Apex of Pyrula ficus Linn. Recent. East Indies. Smooth stage of about 1.7 whorls. Greatest diameter = 2.6 mm.
Page 546 - are not very far removed from the ancestral prototype of annelids and mollusks, we should expect to find in the polyclad a mode of cleavage to which that of the higher forms can in its main features be reduced."
Page 466 - Elytra ample, held vertical with the costal margin meeting below the abdomen, closely reticulated over the whole surface; the costal and apical margins without transverse veins; front continued over on to the superior aspect of the head without