70 SUPPLEMENT ' 



been studied in a sufficiently complete manner in all the 

 principal genera, to render it possible to deduce any clear 

 general conclusion concerning it. 



It appears extremely probable that the two parts of the 

 apparatus are distinct, but that they exist in the same in- 

 dividual, which produces what is termed an incomplete her- 

 maphrodism. This seems at least to be absolutely true of the 

 lumbiici. 



In the terebellae the ovary appears to constitute a white body, 

 depressed, bifurcated behind, occupying the upper face of the 

 abdominal muscular plane, from the head as far as the ninth 

 articulation. Its communication with the exterior is made by 

 a medial orifice, situated on the anterior part of the ventral 

 disc. 



In the pecti7iari(B (first division of the Amphitrite in the 

 text, see note), the female organ is constituted by a pair of 

 oval corpuscles, situated altogether at the anterior part of the 

 body, on each side of the origin of the oesophagus, and which, 

 according to the observations of Pallas, scarcely the size of a 

 double seed of millet during the greatest part of the year, 

 swell early in the spring, and form considerable masses, fill- 

 ing all the anterior part of the body, and composed of a great 

 quantity of white grains. 



The female part of the nereides consists in a series more or 

 less considerable of globular masses, of a yellowish white, 

 grained, placed between each gastric enlargement, without 

 adherence or communication with it, and, on the contrary, 

 terminating by an adherence to the skin, immediately at the 

 upper root of the corresponding appendage. 



In the terebellse the spermatic vesicles are four pair in num- 

 ber, the anterior two being smaller. They are implanted in 

 the interstices, which separate the peduncles of the append- 

 ages from the fourth as far as the sixth ; and their external 

 orifices, in the form of transverse chinks, are perceived, though 



