290 LIONEL JAMES PIOTON. 



The third kind of corpuscle appears in relatively small 

 numbers in Polymnia, but is very abundant in Amphitrite 

 (A. rubra and A. variabilis). On making a small incision 

 in the body-wall of a fresh specimen of this worm, a thick 

 pink liquid comes out. A drop of this examined under the 

 microscope is seen to contain numbers of corpuscles of a 

 striking size and appearance. About 35 fx in their greatest 

 diameter, they are of a flattened oval form (fig. 50), and are 

 filled with pale yellowish spheres which resemble oil droplets, 

 and evidently are the cause of the pink colour of the coelomic 

 fluid in bulk. These droplets are undoubtedly fat. In a 

 cover-slip preparation of coelomic fluid, fixed in absolute 

 alcohol, and stained with Soudan III dissolved in 70 per cent, 

 alcohol, washed with dilute alcohol, and mounted in glycerine, 

 the globules are stained a bright orange-red (fig. 52). If, 

 instead of washing with alcohol, the preparation be washed 

 with ether, the stained fat is removed from the corpuscles, 

 leaving the spherical cavities which contained it empty. 

 There is a large nucleus, somewhat eccentrically placed, and 

 visible only on staining,^ whilst the groundwork of the cell is 

 occupied in the fresh condition with minute greenish granules 

 which do not stain with Soudan III, and may be compared with 

 the discrete granules described by Lim Boon Keng in Luni- 

 bricus. Strongly defined granules of yellow pigment also occur, 

 especially in smaller eleocytes, with little fat (fig. 51) ; and, 

 finally, the cell is enclosed in a distinct cell membrane. 

 These large fat-containing corpuscles may be compared with 

 the eleocytes of Oligochseta, in which Kosa (27) states, on the 

 evidence of Ranvier's fat test, that the granules consist of fat." 



' lu preparatious treated with Elirlich's Lsemateiu, stained curved Hues were 

 often seeu radiating irregularly from the central poiut iu the eleocytes of 

 Amphitrite. I supposed al first that at this poiut there was a centrosjjhere, 

 the whole arraugemeut beiug similar to that described by Rosa (27) iu the 

 eleocytes of Allobophora. In preparatious treated with iron htematoxyliu, 

 however, no ceutrosphere is brought out, so that the appearance remains 

 unexplained. 



2 I have confirmed this observation by the use of Soudan III, on the eleo- 

 cytes of au Allobophora, a common worm in the Villa Ileale, Naples. 



