Approximately 20,000 measurements were made of crabs and cast exoskeletons, chiefly from Boundary bay, southern British Columbia. From size frequencies of crabs under 3 cm. seven modes have been identified as representing the early post-larval instars. Increase in size of animals in the laboratory or in live wells is significantly less than in nature, and leads to erroneous results when applied to growth. The increase per moult decreases from about 40 per cent in the early post-larval stages to about 15 per cent in males of 13.5 cm. and 10 per cent in females of 13.0 cm. Above 10 cm. the males increase more per moult. The intervals between moults become progressively longer with increasing size, and tagging experiments indicate that large crabs moult yearly. Probably to reach the maximum size, seventeen and sixteen post-larval instars are required for males and females respectively. Sexual maturity in female crabs is probably attained during the fourth or fifth year but may occur in the third or the sixth year. The legal size in British Columbia (6½ inches, or 16.5 cm.) is probably attained during the seventh or eighth year. The average duration of life is probably about eight years and the maximum age not more than ten years.

However, the behavior of Cancer magister has been mentioned only briefly (MacKay, 1931 and1942) and very little information is available in the literature concerning this economically important crustacean. It would therefore seem desirable to place on record the available information concerning the behavior of this crab.The observations reported herein were made chiefly at Crescent and at Prince Rupert, British Columbia during the period 1930-34 and 1941. Crescent is located on Boundary Bay, a large and relatively shallow bay in the extreme southern section of British Columbia (see fig. 1). It is the site of an intensive crab fishery characterized by somewhat unusual fishing methods which will be discussed later in this paper.

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Summary An analysis by the method of Huxley of approximately 4000 measurements made on about 1800 individuals of Cancer magister from the Pacific coast of North America is here presented. Slight heterogony has been found in the growth of the majority of its parts. In all aspects of relative growth it is extremely conservative. Changes in form indicate that sexual maturity in the female occurs at a carapace width of about 10 cm. This is confirmed by the size of ovigerous females and by observations of the development of the ovary. The sudden change in the length‐width proportions indicates that sexual maturity is usually attained by a single moult. The size at which male crabs become mature could not be inferred with certainty from the present data. After sexual maturity has been attained the legs of male crabs grow more rapidly than the body and the legs of females continue to grow less rapidly than the body. As a consequence the legs of mature males are longer than those of mature females of corresponding carapace width. A change in the ratio of length to width of the sixth abdominal segment of females has been noted at a carapace width of 7 cm. No other change is known to occur at this size. It is possible that this is a precocious change associated with the approaching sexual maturity. Crabs from south‐eastern Alaska, both male and female, were found to be a little shorter in proportion to their width than the corresponding Boundary Bay crabs. It has been pointed out that most organisms display some heterogony and that bizarre forms must exhibit it to a greater degree than more conservative forms. It has further been pointed out that a strong negative correlation seems to exist between the degree of heterogony and the maximum size of a species. Unfortunately no data justifying speculation upon the causal relationships are available. Cancer magister in all aspects of relative growth displays great conservatism; no high values for k were found for this large and abundant species.

No abstract

The tendency of an animal to turn to the right or left when given a choice is studied here with reference to the hermit crab. The term "left-right tendency" is used in preference to "handedness" since the latter term might be thought to imply the greater use of the right or left claw instead of the general rightward or leftward tendency of the animal when confronted with a choice. Relatively little attention has been given to this problem in so far as the invertebrates are concerned. The work carried out to date has been summarized by Wile 1 who directs attention to the fact that organisms with a left spiral structure tend to move to the right in the ratio of 10 to 1 or greater while animals with a right spiral structure move left predominantly in the ratio of about 2.3 to 1.While hermit crabs can hardly be considered to be spirally constructed yet they do inhabit the shells of animals which are so constructed. For instance, all hermit crabs used in the present experiment were found living in dextrally coiled shells, the majority in Nerita picea, Turbo intercostalis, and Peristernia chlorostoma although twelve other species were also represented. Most marine shells are coiled to the right and hermit crabs show a corresponding modification and degeneration of the appendages of the right side.Under the circumstances would a hermit crab turn predominantly to the right or to the left when the experimental arrangements were such as to offer equal chances?The species chosen for the experiment was Calcinus herbsteii de Man, an attractively colored hermit crab, sometimes reaching 3 inches in length, which is not uncommon near the Marine Laboratory of the University of Hawaii at Waikiki Beach where the experiment was conducted. For this type of experiment C. herbsteii offered the advantage of being an active crustacean; most true crabs would be less satisfactory for this work. C. herbsteii has a large left claw and a relatively small right one; no exceptions to this statement were found although a large number were examined. The one large claw is used to block the opening into the shell into which it fits closely, thus acting as an operculum.The apparatus used consisted of a series of Y-shaped runways made from glass and held together by plastic cement. Each runway was painted black, the floor being sanded while the paint was still wet in order to provide traction. Each was built to the same specifications (6$ inches long with passages \\ inches wide) and when in use was placed in a large tray filled with sea water. The water depth was always sufficient to cover both the hermit crab and its shell. In each case the double end of the "Y" faced the window. Extreme 1 Wile, Ira S.: Handedness Right and Left. Boston, 1934.

1137son,' and Haggard and Greenberg5 i. e., that the formation of methemoglobin by methylene blue and its combination with CN removes the latter from the blood stream is untenable. Furthermore, the objection of Henderson' that methylene 'blue because of methemoglobin formation cannot be used in CO poisoning is also baseless, since the catalytic action of methylene blue as a reversible oxidation-reduction dye is responsible for recovery of the animal, and not its ability to form stoichometric equivalents of methemoglobin. PRelative Growth in the Pacific Edible Crab, Cancer magister

In an earlier paper (1) the tendency of the Hawaiian hermit crab, Calcinus herbsteii, to turn to the left or to the right was reported. Calcinus herbsteii possesses a large left claw and a small right one. Since it seemed possible that the added weight on the left side, resulting from the large appendage on that side, might influence the demonstrated tendency to turn to the left in that species, the experiment was repeated with another species in which right and left claws were approximately equal in size. CUbinarius zebra was chosen for the purpose since it fulfilled this requirement and was readily available in shallow water near the Marine Biological Laboratory in Honolulu where the experiment was conducted.Wile (4) has summarized the evidence concerning "handedness" in animals and has pointed out that organisms with a left spiral structure tend to move to the right in the ratio of 10 to 1 or greater, whereas animals with a right spiral structure move left predominantly in a ratio of about 2.3 to 1. For Calcinus herbsteii the writer (1) found the ratio to be 1.8 to 1. Most species of hermit crabs live in the shells of marine gastropod molluscs and such shells are usually coiled tc the right. Hermit crabs show a corresponding modification of the body with degeneration of the abdominal appendages of the right side.The experiment here reported, like the earlier one with Calcinus herbsteii, was carried out at the Marine Biological Laboratory of the University of Hawaii at Waikiki Beach, Honolulu, Hawaii. The same equipment was used for both experiments and conditions were in all respects similar except that this second experiment was commenced during the spring of 1942 immediately following the final stages of the first experiment.The drawing reproduced as figure 1 was prepared for this paper by Miss Lois Eubank, now of the University of California. The illustration is gratefully acknowledged- THE EXPERIMENTAL ANIMALCUbinarius zebra (see figure 1) is a small species of hermit crab; adults reach a length of approximately 2.5 cm. Members of the species sometimes aggregate (2) thus often making it possible to collect a number of them in one small area. In the Waikiki Beach area the species usually inhabits the dextrallycoiled shells of the following species of gastropod molluscs:-Peristernia chlorostoma Sowerby, Nerita picea Recluz, Nerita neglecta Pease, and Columbella zebra Gray (3); shells of a number of other species of molluscs are less frequently used.In appearance CUbinarius zebra is dark reddish-brown in color and has longi-421