ON A NEW OKGAN IN THE LYCOEIUEA. 391 



I have had the opportunity of examining — namely, Nereis 

 diversicolor, N. macropus, Clp./ N. cultrifera, Gr., 

 Alitta virens, Sars, and Nereilepas fucata, Sav. In all 

 these species the organ resembles that described in N. diversi- 

 color in every particular, as far as I was able to ascertain; but 

 in some cases the specimens were not very well preserved. It 

 is a somewhat remarkable fact that I have failed to find it in 

 two Heteronereid forms (the $ Heteronereid of N. pelagica, 

 and a small c? Heteronereid which 1 have not yet been able to 

 identify) . 



Of other genera, both nearly related to, and far removed 

 from, the Lycoridea, I have examined the following species : 

 Aricia foetida, Nephthys scolopendroides, Eunice sp., 

 Lumbriconereis impatiens, Staurocephalus Ru- 

 dolphii, Sthenelais dendrolepis, Polynoe elegans, 

 Rhynchobolus convolutus, and R. siphonostoma. In 

 none of these forms has any trace of the dorsal ciliated organ 

 been found, and it is to be noticed that all these species have 

 nephridia provided with large and widely open funnels, and 

 short, more or less straight, ducts." 



A short time ago Professor Lankester directed my attention 

 to a very interesting paper by Professor A. Kowalevsky (7) on 

 excretory organs, in which certain segmentally arranged 

 organs, occurring in N. cultrifera, are shortly described. I 

 shall quote the passage in full from p. 71 : '* Das Indigo- 

 karmin [which the animals had taken in] wird meistens von 

 den Blutkorperchen aufgenommen, und zum Teil farbt es in 

 jedem Segmente besondere Organe, welche an der Ruckenseite 

 der Segmente liegen und aus driisenartigen Zellen der Haut 

 bestehen, unter denen man immer eine grosse Anhaufung der 

 Blutkorperchen sieht. Die Stellen, welche so das Indigo- 

 karmin bei Nereis aufspeichern, sind auch an normalen Tieren 

 zu sehen; dies sind Stellen mit Anhaufungen von braunen 



1 I am much indebted to Signer Lo Bianco, of the Naples Zool. Station, 

 for collecting and sending me several species of Nereis. 



^ I hope soon to be able to give a description of the minute structure of 

 the nephridia of some of the genera mentioned above. 



