IN THE ANIMAL KINGDOM. 9 



confirmed. In a subsequent research (Compt. rend. soc. biologic, 1897, 

 xvn, 47) he proved the identity of the blue coloring matter of the bloods 

 of Octopus and Homarus, and in the latter he found two coloring matters 

 corresponding to those described by Jolyet and Regnard (loc. cit.) in the 

 blood of crabs. He confirmed their observations of the behavior of hemo- 

 cyanin towards reflected and transmitted light, and he showed that the 

 reddish coloring matter (tetrorierythrin) takes no part in the change of 

 color caused by oxygenation and deoxygenation. Hemocyanin was found 

 by Fredericq in the bloods of the gasteropods Arion and Helix. 



The list of animals whose blood contains hemocyanin was materially 

 added to by the investigations of Krukenberg (Vergleich. physiol. Studien, 

 1 Rh., 3 Abth., 1880, 66; 1881, 49; 1882, 87, 182; Centralb. f. med. Wis- 

 sensch., 1880, vni, 417), and he added information regarding the behavior 

 of hemocyanin towards C0 2 , CO, and H 2 S, and especially in the direction 

 of indicating the existence of several forms or modifications of hemocyanin 

 which has since received support by the investigations of Howell (p. 10), 

 Cue"not (p. 12), and Couvreur (p. 13). He showed that the blue blood of 

 two cephalopods (Eledone moschata and Sepia officinalis) and of a number 

 of species of crabs (Homarus vulgaris, Carcinus moenas, Eriphia spinifrons, 

 Portunus depurator, Graspus marmoratus, Maia verrucosa, Pilumnus villo- 

 sus, and Squilla mantis) became more or less intensely blue upon agitation 

 with air or oxygen, and more or less decolorized by shaking with CO 2 . He 

 found that the blood of Limna>us stagnalis was scarcely affected by shaking 

 with CO 2 , and he believes that in this species, and also in Helix pomatia 

 and aspera, the coloring matter exists as a body very closely related to 

 hemocyanin. Marked differences were noted in the degree of coloration 

 of the blood and fixity of the O. The blood of Portunus depurator was a 

 very light blue, while the bloods of Homarus, Eriphia spinifrons, and 

 Squilla mantis were a deep indigo blue. In the gasteropod molluscs, crabs, 

 and cephalopods, he noted such differences in the behavior of the hemo- 

 cyanin towards O as to lead him to the belief that this gas is in firmer com- 

 bination in crabs and cephalopods than in molluscs. He also compared 

 hemocyanin and hemoglobin in their behavior towards certain gases. He 

 found, for instance, that after decolorization of the blood with C0 2 the 

 original color was restored by shaking with air, and that when subjected 

 to S0 2 or sulphide of ammonium the blood of crabs and Eledone became 

 yellowish, and that the color could not be restored by agitation with 0, 

 both of which are the opposite to the behavior of oxy hemoglobin. He 

 failed to find any evidence of the presence of hemocyanin in the blood of a 

 number of molluscs. 



Little of importance was added to our knowledge of this important 

 substance during the following decade. Gotch and Laws (British Asso- 

 ciation Reports, 1884; quoted by Lankester, loc. cit.) found hemocyanin 

 or a body closely identical with it in Limulus polyphemus; Halliburton 

 (Journ. Physiology, 1885, vi, 300) reported hemocyanin in the crustacean 

 Nephrops, and he gives the following list of animals in which hemocyanin, 

 hemoglobin, chlorocruorin, hemerythrin, chlorophyl, and tetronerythrin 



