JOURNAL OF CONi^KOLOGY. 363 



Sphaerium corneum upon the tarsus of Dytiscus 

 marginalis. — On 27th August last, while searching for shells 

 in a pond at West Barkwith, in Lincolnshire, I procured a 

 female Dytiscus marginalis with a Sphtzriii77i corneiwi attached 

 to its right front tarsus. The shell, which enclosed one joint 

 only of the tarsus, was of fair size, measuring 10 mill, in width. 

 On placing the beetle in water it -was ascertained that when 

 motionless it frequently supported the shell with its middle and 

 left front legs, thus relieving the stress upon the leg to which 

 the shell was attached. Occurrences similar to the above, 

 records of which have appeared from time to time, are doubt- 

 less of significance when viewed in connection with the distri- 

 bution of the freshwater shells. — H. Wallis Kew, London, 3rd 

 .September. 



The Red Fluid emitted by Planorbis corneus. — 

 it is well known that this species emits a red-colored fluid from 

 its pulmonary aperture on being killed either in hot water or 

 spirit. Professor Ray Lankester some years ago made the 

 ■interesting discovery that hsemoglobin is present in the plasma 

 of the haemolymph in this species, and the consideration struck 

 me as worth investigating whether the emitted red fluid was 

 haemolymph or not. If it is such it will give the tests for 

 haemoglobin ; and I have found this to be the case. A spectro- 

 scopic examination gave the two absorption hands between D 

 and E of Frauenhofer's lines of the spectrum ; and on testing 

 with ozonic ether and tincture of guaiacum it gave the usual 

 blue color. How this haemolymph gets into the pulmonary sac 

 is indeed a questionable point, and a somewhat difficult one to 

 settle by any experimental method. I would make the sugges- 

 tion—which seems the most probable one to me — that it is 

 extruded into the lung sac by reason that the walls of the 

 circulus venosus pulmonis or of the vessels constituting the 

 ■pulmonary plexus are ruptured as the result of a last and forcible 

 expiratory movement of the muscular floor of the mantle-cavity. 

 — J. W. Williams, D.Sc. 



