268 NEW YORK STATE MUSEUM 



In Gasteropoda, as well as in Cephalopoda, Crustacea and 

 Arachnida the function of respiration is brought about by an 

 albuminoid substance analogous to hemoglobin, but containing 

 copper instead of iron, this substance, which Fredericq names 

 haemocyanin, forming a yery unstable combination. 



The saline matter contained in the blood of the Helix is 

 about 1.075;^; in Li max about 1.115^. 



Touching the color of the blood, Mac Munn^ says in regard to 

 the blood of Helix pomatia: ^^It assumes a distinct blue tint 

 on exposure to the air, and gaye no absorption bands, but ab- 

 sorbed a little of the yiolet end of the spectrum. On treatment 

 with ammonia its color was not so well marked, and it had a 

 partially reddish tinge, but no bands could be seen, and after, 

 treatment with acetic acid did not remoye the color." 



One time I drowned 12 indiyiduals of P. a 1 b o 1 a b r i s, 

 leaying them, as usual, in the water about 48 hours. The blood 

 in the arteries of all these specimens had coagulated and turned 

 a dark purple black in color, so that the course of the arteries 

 could be as distinctly traced as if they had been injected. I am 

 unable to account for this phenomenon, as of scores of specimens, 

 treated in the same manner, these were the only specimens 

 coagulated and colored, though the others were kept in the same 

 box and fed on the same kind of food. 



E"ervoiis system 



The nervous system (pi. 12) consists of fiye distinct sets of 

 ganglia, and four ganglionic swellings, and the commissures con- 

 necting them or proceeding from them. The principal ganglia 

 are the supra-esophageal^ the infra-esophageal, consisting of two 

 sets, and the two buccal ganglia. The ganglionic swellings, or 

 ganglia, are situated at the extremity of the tentacles. The 

 ganglia corresponding to the one situated on the dorsal surface 

 of the stomach inLimax maximus I haye not obseryed in 

 P 1 y g y r a. 



When the animal is extended, the supra-esophageal ganglia 

 are situated just aboye the esophagus, immediately posterior to 



1 Quart, jour, micro, sci. 1885 



