HEART-BODY, ETC., OP CERTAIN POLYCH^TA. 301 



Fig. 33. — Polymnia nebulosa. Larva (ten pairs of chsetae). Pigmented 

 patcli on wall of ventral vessel. 



Fig. 34. — Sip lion ostoma diplochsetos. Sketch showing an attach- 

 ment of the heart-body to the heart-wall ; fresh. D (Zeiss). 



Fig. 35. — Polymnia nebulosa. Sagittal section of posterior end of 

 heart-body in the larva, showing communication of its cavity with the coeloni 

 in course of obliteration, yy. Blood red, nuclei blue. x. Point where the 

 heart-wall is continuous with the wall of the heart-body. 



Fig. 36. — Polymnia nebulosa. Sagittal section of posterior end of 

 heart-body at an earlier stage than in Fig. 35. ^y. Blood yellow, nuclei 

 blue. 



PLATE 22. 

 CffiLOMic Fluid. 

 Siphonostoma diplochsetos. 

 Fig. 37. — Oval corpuscle (fixed in alcohol ; stained hsemalum and eosin). yV- 

 Fig. 38. — Problematical bodies (liajmalum, &c.). D (Zeiss). 

 Fig. 39. — Problematical body ; fresh, ^y. 



Trophonia. 



Fig. 40. — Fusiform coclomic corpuscle, with stalk. (Methyl green and 

 eosin.) Jj'. 



Fig. 41. — Stellate corpuscle. (Formol, alcohol, and acetic mixture, &c.) y^'- 



Fig. 42. — Amaboid corpuscle ; fresh, ^y. 



Fig. 43. — Problematical body ; fresh. D (Zeiss). In the cellular envelope 

 fat droplets are seen. 



Figs. 44—46. — Amphitrite variabilis. Fusiform corpuscles, j^'. 

 Fig. 46 shows a granule stained with hsemalum. 



Fig. 47. — Young Polymnia nebulosa. Coelomic corpuscle, yy. 



Amphitrite (variabilis and rubra). 



Fig. 48.— Granular corpuscle. ^'. 



Fig. 49. — Granular amoeboid corpuscle ; fresh. ■^' . 



Fig. 50. — Eleocyte; fresh, showing fat and pigment spherules, and granu- 

 lar protoplasm. The cell-envelope is distinct. 



Fig. 51. — Smaller eleocytes, with little fat and well-marked pigment granules. 

 Osmic, bichromate of potash, hsematein. y\-'. 



Fig. 52. — Eleocyte. Fixed in absolute alcohol, stained with liaimalum ; 

 fat stained with Soudan iii ; granulated cell-protoplasm unstained. 



VOL. 41, PART 2. — NKW SEBIES. X 



