. Journal of morphology. an increase incells of a given kind. These primordia form chiefly on the oralside of the egg, whereas the greater part of the aboral hemisphereis covered by the large cells of the posterior cell plate. As a cpn-sequence the number of cells visible from the aboral pole at theperiod of the closure of the blastopore does not differ greatly innumber in the different species; whereas the cells visible from theoral pole differ greatly in number in the different species, therebeing more than three times as many in C. adunca as in C. planaat the time when the blastopore closes
. Journal of morphology. an increase incells of a given kind. These primordia form chiefly on the oralside of the egg, whereas the greater part of the aboral hemisphereis covered by the large cells of the posterior cell plate. As a cpn-sequence the number of cells visible from the aboral pole at theperiod of the closure of the blastopore does not differ greatly innumber in the different species; whereas the cells visible from theoral pole differ greatly in number in the different species, therebeing more than three times as many in C. adunca as in C. planaat the time when the blastopore closes, and in later stages thisdisporportion becomes much greater. Table 5 gives the diameter of the egg and of the ectodermalplate in different species of Crepidula, at the time when the ecto-meres are first separated from the macromeres; also the approxi-mate number of ectoderm cells, visible from the oral and theaboral poles at the time of the closure of the blastopore, in thedifferent species. BODY SIZE AND CELL SIZE 177.
Size: 1607px × 1555px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1, booksubjectphysiology, bookyear1912
