. Amphioxus and the ancestry of the vertebrates. Amphioxus; Sea squirts; Hemichordata. CEPHALODISCUS. 265 laterally and ventrally it is produced into a free fold to form the above-mentioned operculum. The collar-region contains a section of the coelom which is precisely homolo-. Fig. 127. — Longitudinal sagittal section through an adult Cephalodiscus. CAfter ) The section is supposed to be taken sufficiently to one side of the middle line to allow of the representation of one of the ovaries and one of the proboscis-pores. a. Anus. Trunk-coelom. Collar-ccelom. ch. Notochord. i
. Amphioxus and the ancestry of the vertebrates. Amphioxus; Sea squirts; Hemichordata. CEPHALODISCUS. 265 laterally and ventrally it is produced into a free fold to form the above-mentioned operculum. The collar-region contains a section of the coelom which is precisely homolo-. Fig. 127. — Longitudinal sagittal section through an adult Cephalodiscus. CAfter ) The section is supposed to be taken sufficiently to one side of the middle line to allow of the representation of one of the ovaries and one of the proboscis-pores. a. Anus. Trunk-coelom. Collar-ccelom. ch. Notochord. int. Intes- tine, m. Mouth. .Nervous system. op. Postoral lamella (operculum). ov. Ovary: the oviduct is deeply pigmented, Praeoral ccelom (cavity of buccal shield). pk. Pharynx. /./. Proboscis-pore. ped. Base of pedicle. St. Stomach. gous with the collar-cavities of Balanoglossus. As in the latter form, it communicates with the exterior by a pair of collar-pores which open at the level of the Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Willey, Arthur, 1867-. New York, London, Macmillan
Size: 1327px × 1883px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, bookpublishernewyo, bookyear1894
