PLATE IL 



Colours : see Plate I. 



Fig. 27 : see Plate I. 



Figs. 41 — 56. Dinomenia Hubrechti. 



Fig. 41. Dinomenia Hubrechti, 4 > , from a spirit-specimen. 



Fig. 42. Spicula, 316 x. A of the body-wall, B along the ventral groove. 



Fig. 43. Reconstruction of the anterior extremity out of transverse sections. 39 X. a mouth-cavity, 



(cirrhi not indicated) b cavity in which the pharynx opens out; e dorsal and proximal coecum. 

 Figs. 44 — 47. Schematic transverse sections along the lines AB — G H ol fig. 43. c muscle separating cavity 



a and cavity b, cc cartilaginous cells. 39 X. 

 Fig. 48. Transverse section through the radula. 148 > . In muscle, sg salivary gland. 



Fig. 49. Radula-teeth and fragments. 430 X- 



Fig. 50. Transverse section through the radula-sac. 215 • . A more proximally, B more distally. 



Fig. 51. Reconstruction of the posterior extremity, out of transverse sections, dorsal view. a vesicula 



seminalis, /' receptaculum seminis, es copulation-spiculum. 23 X. 

 Figs. 52 — 55. Schematic transverse sections along the lines AB — G H of fig. 51. 23 • . es copulation-spicula. 

 Fig. 56. 6 Transverse sections through the pericardium and the heart. 75 X- a and b invaginations 



of the distal and dorsal pericardial wall, forming together the atrium b 4- a. c invaginations 



of the dorsal pericardial wall which form the ventricle, d see text. 



Figs. 57 — 59. Proneomenia sp. 



Fig. 57. Reconstruction of the posterior end out of transverse sections. Dorsal view. a proximal offset 



of the cloaca, b coecum of the cloaca-ducts, e copulation-spiculum. 40 

 Figs. 58 — 59. Schematic transverse sections along the lines AB — CD of fig. 57. es copulation-spiculum. 37 X- 



Figs. 60 — 75. Dinomenia verrucosa. 



Fig. 60. Dinomenia verrucosa, drawn from life by Mr. HUYSMANS. Natural size. 



Fig. 61. A young specimen, 4 X, drawn from a spirit-specimen. 



Fig. 62. Spicula, 125 X. A of the body-wall, B and C along the ventral groove, D around the cloaca- 



opening. 



Fig. 63. Reconstruction of the anterior part of the specimen of fig. 60 out of transverse sections. 4 X. 



a part of the mouth-cavity filled with cirrhi, b little dorsal coecum, c fold of the dorsal 

 wall of the mouth-cavity, d ventral coecum, r radula-sac, e tubular ventral appendage of 

 the pharynx, s g salivary gland, g g genital gland, m m pharyngeal muscles. 



Fig. 64. Transverse section through the appendage e and the salivary gland s g. 88 X. 



Figs. 65 — 6j. Radula-teeth and fragments. 88 X. 



Fig. 68. Transverse section through the radula and radula-sac, b basal-membrane, / tooth. c pedicle. 39 X. 



Fig. 69. Transverse section through the radula at the point where it bends into the radula-sac. 50 X- 



Fig. 70. As fig. 63, anterior part of a young specimen. 12 •'. o opening of the ventral pharyngeal 



appendage. 



Figs. 71 — yj. Schematic transverse sections through the anterior part, along the lines AB — NO of fig. 63. 

 4 •. rs radula-sac, r radula. 



