PLATE II. 



Colours : see Plate I. 



Fig. 27 : see Plate I. 



Figs. 41 — 56. Dinomenia Hubrechti. 



Fig. 41. Dinomenia Hubrechti, 4 X, 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) /> cavity in which the pharynx opens out; c dorsal and proximal coecum. 

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

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

 48. Transverse section through the radula. 148 ■ . /« muscle, s^ salivary gland. 

 Radula-teeth and fragments. 430 X. 



Transverse section through the radula-sac. 215 X. A more proximally, B more distally. 

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



seminalis, d receptaculum seminis, cs copulation-spiculum. 23 X. 

 Schematic transverse sections along the lines AB — GH of fig. 51. 23 X. cs copulation-spicula. 

 56. 6 Transverse sections through the pericardium and the heart. 75 X. a and d invaginations 

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

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



Figs. 57 — 59. Froneomenia 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, c copulation-spiculum. 40 <. 

 Figs. 58—59. Schematic transverse sections along the Wnes A B— CD of fig. 57. cs copulation-spiculum. 37 ■ . 



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 :■ . 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, c tubular ventral appendage of 

 the pharynx, sg salivary gland, gg genital gland, mm pharyngeal muscles. 



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



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



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



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



Fig. 70. As fig. 61, anterior part of a young specimen. 12 X. opening of the ventral pharyngeal 



appendage. 



Figs. 71—77. Schematic transverse sections through the anterior part, along the lines AB—NO of fig. 63. 

 4 X. /' .f radula-sac, r radula. 



