The Composition of the Blood of the Shore Crab, Carcinus Moenas Pennant, in Relation to Sex and Body Size

Abstract

1. The influence of sex and body weight on the concentration of sulphate and chloride ions in the blood of the common shore crab was investigated. 2. Blood chloride increased in both sexes until a maximum was reached at a weight of about 35 g.; thereafter it fell with increasing body weight. 3. Over the whole size range blood chloride was higher in females than in males. This difference was highly significant for animals over 35 g. body weight; below 35 g. however, there was no significant difference between the sexes. 4. Over a restricted size range blood sulphate of males was significantly higher than that of females. 5. Results of the present work have been discussed in relation to those reported earlier for conductivity and total O.P.