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THE AMERICAN NATURALIST [Vol. LIV 



are brightly pigmented, but the girdle of the chiton is never 

 raised more than a few millimeters from the surface upon which 

 the animal may be resting, and while above water, in the inter- 

 tidal zone, even this minute elevation occurs only along a short 

 length of the mantle at a time. If it be answered that these 

 chitons frequently creep over one another, it should be remem- 

 bered that in the Placophora there are no tentacular eyes upon 

 the head, and in the genus Chiton no extra pigmental mcgaMhete 

 eyes upon the valves ; so there is, after all, no opportunity for 

 sex-recognition through color (a fantastic idea, for other rea- 

 sons also). That the coloration of the soft parts is ever visible 

 to other animals seems equally improbable. Certain small isopods 

 (Spharoma) commonly frequent the mantle "chamber" of 

 Chiton tiiburuhitus, but they are found indifferently in the com- 

 pany of either sex. It is necessary to conclude that, so far as 

 color is concerned, the pink or orange hue of the body of the 

 female Chiton tuberculatas is of no ethological significance; the 

 nature of the pigment, its association with the growing ovary, 

 its progressive changes in the ovary itself, and its presence in 

 the blood, make of this case a most excellent illustration of the 

 "metabolic-accident" conception of certain types of animal 

 coloration. 



W. J. Ckozier 



Dyer Island, 



ON THE ALKALINITY OF THE SEA WATER IN 

 LAGOONS AT BERMUDA 1 

 The present land-form of Bermuda, resembling in certain 

 respects the configuration of many "coral" islands, was em- 

 ployed by Ileilprin- ;is an example of atoll formation through 

 basic subsidence. The southeastern segment of the proto-Ber- 

 muda land mass, now the only area above water, in addition 

 exhibits three distinct "sounds," or lagoons: Great Sound, 

 Harrington Sound, Castle Harbor. These lagoons Heilprin also 

 conceived to have origin;. ted t lin m-h lord suUidmces. Fewkes 3 

 had earlier considered the origin of these lagoons, stating his 

 belief that they, as well as the form of the islands as a whole, 



1 Contributions from the Bermuda Station for Research, No. 114. 



2 Ileilprin, A., 1889, "The Bermuda Islands," Philadelphia, [vi] + 231 

 pp., 17 pi. 



a Fewkes, J. W., 1888, Proc. Host. 8oc. Sat. Ilitt., Vol. 23, pp. 518-522. 



