MisceUuiu'ous. 281 



The posterior brain, wliich, in tliis form, is distinctly dorsal, ia 

 very stronj::ly developed ; it gives off two large nerves which pass 

 into the caruncle. The latter organ, which was misinterpreted by 

 Ehlers (1804), has recently been described by Mcintosh (1894), 

 who, however, did not recognize its true nature and saw in it 

 nothing but some fibres. Its innervation, however, shows that the 

 caruncle is nothing else than the nuchal ort/itn. It is formed, in 

 fact, by three elongated folds of the body-wall. One of these folds 

 is of greater length, and is placed hetweon the other two ; its lower 

 edges are nnited to the inner edges of the lateral folds. Vibratile 

 furrows, which are very distinct and parallel, run the entire kngth 

 of the folds. There are four of them on the median fold, and only 

 two on the lateral ones. Two of the vibratile furrows pass 

 from the caruncle on to the cephalic lobe, and extend as far as the 

 paired antennai. 1 shall describe this arrangement in detail else- 

 where. I am likewise unable to dwell here upon the histological 

 structure of the caruncle, which, moreover, does not differ essentially 

 from that of the same organs in other Polychaites. The three folds 

 indicated above are entirely similar to the occipital lappets (ailerons 

 occipitaux) of e. g. ^m?</^oiri7/i.s\ Their union into a single mass 

 only disguises the primitive condition which is still represented in 

 Euphrosine triloba, Ehlers. 



The glandular organs which, according to Mcintosh (1894), are 

 found on each side of the caruncle, are nothing but masses of pigment 

 deposited in the posterior lobes of the brain. Similar masses are 

 also found along the pedal nerves, and also in other Polychaetes (e. g. 

 ventral chain of Eunice). Veritable glandular organs, however, 

 exist. These are two pyriform masses, constituted by greatly 

 elongated hypodermic gland-cells. These organs belong to the palpi ; 

 for if the bodies of the cells are situated behind the brain, their 

 ducts open on the surface of the palpi. 



In the genus Spinther the tendencies indicated at the commence- 

 ment of this note have been realized much more completely. The 

 parapodia of the first segment have become united in front of the 

 cephalic lobe. The caruncle has disap{)carcd equally with the palpi 

 and the paired antenna}. The unpaired antenna of the Amphino- 

 midse alone persists, with its four eyes at its base. 



The presence of four of these organs upon the dorsal face and at 

 the base of the unpaired antenna dearly indicates that Sjiinther 

 cannot be the direct descrndant of Eujthrosine. These two genera 

 form two distinct branches from the stem of the AmphinomidiX}. 

 The tendency towards radial symmetry which is displayed in Sjiinther 

 as in Eupltrosine must not be attributed to a direct parental con- 

 nexion between the two forms. The explanation of the phenomenon 

 is to be sought in a convergent evolution occasioned by a mode of 

 life almost as sedentary as that of fixed animals. — Compies Rendus, 

 t. cxix. no. 20 (December 24, 18{>4), pp. 1220-1228. 



On the Develojiment of the Kidnei/ and of the Orlomc in Cirriprdes. 

 hy A. (Jkcvel. 



In the paper which 1 havi- published in the ' Archives deZoologie 



