HEART-BODY, ETC., OF CERTAIN POLYCHiETA. 269 



Guido Schneider (31, B) shows that in the heart-body of 

 Pectinaria hyperborea irou is present, and increases in 

 quantity after injection of " Ferrura oxidatum saccharatum " 

 into the body-cavity ; but only the preliminary notice of his 

 work is published, and his interesting researches may be ex- 

 pected to throw much light on the subject. 



Monticelli (25) gives a very minute description of the heart 

 and heart-body of Polyophthalmus, correcting the earlier de- 

 scription by E. Meyer (23, A, p. 815). 



Finally, in a recent paper on the Ampharetidae (13), Fauvel 

 deals with the heart-body of that group. He describes it as a 

 solid organ bifurcated at the base, where it is inserted into the 

 dorsal face of the stomach. He regards it as fulfilling several 

 functions. It supports the heart in the first place, especially 

 when the pharynx is everted ; and it also acts as a valve. It 



whilst. I first noticed the bow-shaped corpuscle in a fixed and stained film. 

 In such preparations they are much easier to find than in fresh hgemolymph, 

 though I subsequently found them in the fresh state. I may say that I found 

 at least one bow-shaped corpuscle in every specimen of hsemolymph of each 

 individual of Notomastus profundus which I examined. 



The bow is of a pale yellow colour, and highly refringent. Dr. Paul Mayer 

 kindly examined it with polarised light, and pointed out that it was always 

 of a different colour from the rest of the field. Its shape is that of a strung bow, 

 the tips being slightly recurved. Like the large brown granules which 

 occupy the hsemoglobinous corpuscles, it is insoluble in cold caustic potash, 

 whether in 25 per cent, solution or weaker ; nor was it soluble when heated 

 in potash solution up to 120° C. It is therefore probably of a chitinous 

 nature, if not actually chitiu. The protoplasm completely encloses the rod, 

 forming, however, a very thin layer over the ends and the convex side. It is 

 colourless, often slightly vacuolated, and frequently exhibits long filamentous 

 projections, which may be seen in the fresh state making slow movements. 

 It is noteworthy that these projections extend from the protoplasm on the 

 convex side of the rod, as well as from the body of the cell, which, of course, 

 lies on the concave side. The nucleus lies on the concave side, and 

 slightly lateral to the rod. It is stained, though usually not strongly, with 

 hsematoxylin. The rest of the protoplasm is almost unstained, except at the 

 ends of the rod, the cap which covers the latter being often intensely coloured. 



Small fusiform corpuscles containing a clear straight rod occur also in the 

 hsemolymph, and may be the young stages of the rod-cells. Dr. Eisig, how- 

 ever, was inclined to think that the rod-coutaining corpuscles are parasitic. 

 VOL. 41, PART 2. NEV7 SERIES. T 



