. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SALT REQUIREMENTS OF LIGIA 497 These spines, which are usually long, are also used as swimming fins and feelers as in other species of Ligia. It is probable that Ligia enters the sea to release the young from the brood pouch for this occurred only in submerged specimens. An examination of the gut contents revealed vegetable debris and unicellular algae. According to Hewitt (1907) L. oceanica feeds largely on decaying vegetable matter. L. exotica is described as omnivorous by Pearse (1931). Although Pearse (1929) is undoubted
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. SALT REQUIREMENTS OF LIGIA 497 These spines, which are usually long, are also used as swimming fins and feelers as in other species of Ligia. It is probable that Ligia enters the sea to release the young from the brood pouch for this occurred only in submerged specimens. An examination of the gut contents revealed vegetable debris and unicellular algae. According to Hewitt (1907) L. oceanica feeds largely on decaying vegetable matter. L. exotica is described as omnivorous by Pearse (1931). Although Pearse (1929) is undoubtedly correct in pointing out that food supply alone is probably not the most important factor in determining the habitat of littoral forms, yet it is of interest to note that Ligia baudiniana subsists largely on the green coating of rocks in the intertidal FIG. 1. Ligia baudiniana wetting the gills by the capillary action of the uropodal spines which are dipping into the sea. CONCENTRATION EFFECTS As a basis for comparison for subsequent experiments, the longevity of the isopods was first determined in sea water, air, and in fresh water. Individual specimens, carefully collected to avoid injury, were placed in finger bowls containing 100 cc. of water or solution. The average duration of life was only four hours in distilled water, seven and one-half hours in fresh water and thirty-four hours in sea water (Table I). The maximum longevity is also given in the tables. Sea water, changed every twenty-four hours, gave an average duration of life of fifty-eight hours, and in running aerated sea water the average longevity was one hundred and ninety-two hours, but the maximum was recorded for unchanged sea water. The large surface exposed to the air in the finger bowls permitted considerable diffusion of O2 and CC>2 as is indicated by the maximum of twelve and one-half days in unchanged sea water. In dry glass dishes the average duration (and the maximum) was eleven hours, but
Size: 2605px × 960px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
