266 LIONEL JAMBS PIOTON. 



heart-body with the vascular walls suggest a similar source 

 of origin for it. He regards the organ as a blood-pigment 

 gland. 



Miss Buchanan (6, A) found a heart-body in Hekatero- 

 branchus Shrubsolii; and also (7, B) a structure, which is 

 wanting in the adult, in the dorsal vessel of the developing 

 Magelona. She regards it as a larval heart-body, and supposes 

 that on its dissolution it forms the blood-corpuscles. 



Cuenot (9"), who examined chiefly Nicolea venustala, 

 describes cells in the heart-body as enclosing a number of 

 refringent green granules. " J'ai vu/' he says, '' plusieurs 

 fois les cellules vertes de la glande eraettre de courts pseudo- 

 podes et faire saillie au-dessus de leurs voisines pour etre, sans 

 aucun doute, entrainees plustard par les courants sanguins; le 

 corps cardiaque est done une glande lymphatique parfaitement 

 caracterisee." Further, he agrees with Meyer in regarding it 

 as also eflfecting a transformation of colourless albuminoids 

 into haomoglobin. 



Schaeppi (29), in his interesting paper on the chloragogen 

 of Ophelia, though his chief purpose is a study of the re- 

 markable chitinous rods which occupy certain of the cceloraic 

 fluid corpuscles of that worm, yet gives in addition a careful 

 description of the heart-body, and also of certain peculiar 

 intra-vascular connective tissue which occupies the perivisceral 

 sinus posterior to that organ. This latter tissue begins where 

 the heart-body ends ; and, though the author shows that it 

 contains difi'erent substances from those in the heart-body, the 

 description suggests very strongly that it is an accessory part 

 of the heart-body prolonged backwards from the short anterior 

 dorsal vessel or heart into the sinus which surrounds the gut. 

 The heart-body itself is a flattened band, of a bluish-white 

 colour, occupying the cavity and attached to the walls of the 

 heart. It consists of a homogeneous groundwork strewn with 

 connective-tissue cells. Besides these there also occur cells 

 occupied with peculiar green pigment granules, similar to 

 others found in the thoracic sinus, but only rarely in the rest 

 of the blood system. There are green granules also in some 



