ON THE ZOOLOGICAL STATION AT NAPLES. 375 



of the alimentary canal, but whether this applies to the anterior branchial 

 portion, as it does to the posterior portion, is doubtful. 



The heart contains a cardiac body, similar to that present in the 

 Cirratulidte, Terebellidte, Amphictenidte, Ampharetidce, and Hermellidje, 

 all families with coloured blood. I can confirm the observations of J. T. 

 Cunningham on its anatomical relations and those of Jourdan on its 

 histological features ; but the latter has fallen into an old error by inferring 

 from its colour, &c., that it is a gastral csecum. In Siplionostoma there 

 is no connection and not even contact with the gut. Its cells are, in 

 hardened specimens, crowded with green grannies, which also occur in the 

 clotted blood, and the organ is probably concerned in the formation of the 

 blood-pigment. The chloragogenic cells of other polyclicet worms are 

 peritoneal, and in Siplionostovia the manner in which different portions 

 of the cardiac body are attached to the wall of the heart gives reason to 

 believe that its cells are peritoneal in origin. At the hinder end of the 

 heart there are indications of the cardiac body being paired. 



The ' glandes en tubes,' ' glandes salivaires,' of earlier writers have 

 been conjectured to be nephridia by Wiren, Cunningham, and Jourdan, 

 but these investigators failed to discover the nephi'idial funnel. This is 

 situated at the level of the hinder border of the supra-oesophageal gan- 

 glion. It resembles those nephrostomes in Ajjhrodite which serve as vasa 

 deferentia, in its being very wide and extending from dorsal to ventral 

 surface. The opening is directed forwards, inwards, and downwards, and 

 is close to the anterior end of the coelom. It is lined by a single layer of 

 cells bearing long stout flagella. The funnel leads into a narrow tube 

 with an intercellular lumen, whose wall is composed of a single layer of 

 nephridial cells and an investing layer of peritoneum. This tube passes 

 straight back as far as the 12th segment, there bends on itself and runs 

 straight forward, becoming much dilated at the level of the oesophagus, 

 in some cases filling almost the whole of the perivisceral space. The 

 external aperture of the nephridium is anterior to the first bundles of 

 set£e on a conical papilla, one on each side, close to the protuberance 

 bearing the eyes and to the inner side of the branchial filaments. The 

 two limbs of the V-tube formed by the nephridial duct are closely apposed 

 along their entire length, and the investing peritoneum forms a simple 

 sac, as though it had been pushed inwards by the nephridium as a 

 whole ; there is no peritoneum between the apposed surfaces of the two 

 limbs. In their position and simplicity of structure the nephridia re- 

 semble the single pair of thoracal nephridia in the Serpulidse. In the 

 Chlorhfemidge, however, abdominal nephridia do not occur. There are 

 no blood-vessels in the nephridia. Ova have been seen in the nephridia 

 of Chlorhcema by Williams, and he concluded that the segmental organs, 

 as he calls them, were genital glands. Here, then, the same organ 

 functions as an excretory organ and as a gonaduct. 



I was eventually successful in experiments on feeding with carmine, 

 and was able to keep the worms alive for a fortnight in filtered sea-water 

 containing finely-powdered carmine in suspension, by passing a constant 

 current of air through the Avater. As regards the nervous system and 

 sense-organs and the reproductive organs, I can at present add nothing 

 to the descriptions of Grube, Jourdan, and Jaquet. 



The zoological position of the Chlorhsemidae has often been altered. 

 Gmbe, who is entitled to speak with authority, places them between the 

 Errantia and the Tubicola, but I am inclined to believe that they wiU. 



