. Bulletin - United States National Museum. Science. 516 BULLETIN 100, UNITED STATES NATIONAL MUSEUM Genus ACTISECOS Canu and Bassler, 1927 The zooecia are tubular, swollen at their base; the frontal is a tremocyst with very small pores. The ovicell is peristomial and placed on the dorsal. The aperture is ogival and buried at the bottom of a long peristomie. The base of the zooecia is hexagonal. Genotype.—Actisecos regularis Canu and Bassler, 1927. Fig. 214. Genus Orthoporidra Canu and Bassler, 1927 A-I. Orthoporidra compacta Waters, 1904. A. Zoarium, natural size. B. Por- tion of a z
. Bulletin - United States National Museum. Science. 516 BULLETIN 100, UNITED STATES NATIONAL MUSEUM Genus ACTISECOS Canu and Bassler, 1927 The zooecia are tubular, swollen at their base; the frontal is a tremocyst with very small pores. The ovicell is peristomial and placed on the dorsal. The aperture is ogival and buried at the bottom of a long peristomie. The base of the zooecia is hexagonal. Genotype.—Actisecos regularis Canu and Bassler, 1927. Fig. 214. Genus Orthoporidra Canu and Bassler, 1927 A-I. Orthoporidra compacta Waters, 1904. A. Zoarium, natural size. B. Por- tion of a zoarium, X25. The lower edge of the oral aperture is straight. Above the oral aperture there is a long process bearing an avicularium with a triangular mandible. The zooecia are porcellaneous. 24 tentacles. C. Operculum, X85. It is straight below, and the muscular attachments are quite at the distal end. D. Mandible from small avicularium on the zooecium, X85. E. Rostral man- dible, X 85. F. Mandible of vicarious avicularium. (A-F. After Waters, 1904.) G. Section through a zooecium showing tentacles, ovaria and ova, and the wall of the compensatrix, X85. H. Ovarium, X250. I. Wall of the tentacular sheath, X750. The tentacular crown is three or four times thicker and shows the darkly stained longitudinal muscular band, a character which does not appear to exist in the other genera of the family. (G-I. After Waters, 1905.) This genus very much resembles Ascosia Jullien, 1881, but differs from it in having 6 cells around the ancestrula, in the absence of oral avicularia and in the peristomial and not recumbent ovicells. Waters was in error in comparing Ascosia with Mamillopora. The differences are great for Ascosia belongs to the Pentapogona according to the figure of Jullien while Mamillopora has 6 cells around the ancestrula. Ascosia is ornamented with long peristomies. The recumbent ovicell is borne on the peristomie in Ascosia and by the zooecium in Please note
Size: 2088px × 1197px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorun, bookcentury1800, bookdecade1870, booksubjectscience
