. Fig. 2. Chart showing the distribution of Periphylla hyadnthina, Steenstrup, in the South Atlantic and Southern oceans. with 400 individuals, separated by the stratum of 650 m. with 72 specimens only. The upper strata show no increase in the numbers of specimens either. Broch's table on p. 9 on regina demonstrates nothing in this respect, the figures being too scanty. My Table III also shows that an increase in number with depth does not exist. The numbers show a maximum occurrence for each stage, which lies for dodecabostrycha and hyadnthina at 750-1000 m. and for regina at 1250-1500 m. It
. Fig. 2. Chart showing the distribution of Periphylla hyadnthina, Steenstrup, in the South Atlantic and Southern oceans. with 400 individuals, separated by the stratum of 650 m. with 72 specimens only. The upper strata show no increase in the numbers of specimens either. Broch's table on p. 9 on regina demonstrates nothing in this respect, the figures being too scanty. My Table III also shows that an increase in number with depth does not exist. The numbers show a maximum occurrence for each stage, which lies for dodecabostrycha and hyadnthina at 750-1000 m. and for regina at 1250-1500 m. It is possible that an increase takes place towards these optima from the surface, in deeper layers a decrease of numbers may take place (see forma regina). An interesting difference between Broch's and my material is, that the maximum occurrence of the Michael Sars specimens of hyadnthina is found in 500-600 m., but that of the Discovery specimens in 750-1000 m. As to regina my results agree in general with those of Broch.
Size: 2804px × 1783px
Photo credit: © The Bookworm Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, booksubjectocean, booksubjectscientificexpediti
