PLATE V. 



Fig. I 1 8. Pneumonoderina ln'terocotyhtin n. sp. Ventral view. 6 X. 



Fig. ii8^-J. Lateral gill of the same. 



Fig. iiSi). Posterior gill of the same, dorsal view. 



Fig. 119. Acetabuliferous appendage of the same; out-stretched, from the inside. 



Fig. 120. Fneuuionodcnna pyginaciini n. sp. Ventral view. 10 X. 



Fig. 121. Posterior gill of the same, aboral view, d, dorsal; v, ventral. 



Fig. 122. Acetabuliferous appendage of the same; out-stretched, from the inside. 



Fig. 123. Some larval Pneiimonoderma, ventral view. 10 X. Strongly contracted. 



Fig. 124. Central nervous system oi Fni'iononodcruia mcditcrravcuiii (van Ben.). Dorsal view. — Pedal nerves 



and cerebro-buccal connectives not figured. 

 c, cerebral ganglion; a, cerebro-pedal connective; b, cerebro-pleural connective;/, pedal ganglion; 



//, pleural ganglion; plv, pleuro- visceral connective; v, visceral ganglion. 

 I, optic nerve; 2, olfactory nerve; 3, auditory nerve, turned to the front; 4, nerve to the labial 



tentacle; 5 — 7, nerves to the proboscis, the lips and the buccal appendages; 13, 14, pleural 



nerves to the cervical region; 15 — 17, nerves to the envelop of the visceral mass; iS — -19, 



nerves to the viscera. 

 Fig. 125. Pedal ganglia of the same. Dorsal view. 



ap, anterior pedal commissure; /, pedal ganglion; a, cerebro-pedal connective, ot, otocyst. 



8, nerve to the foot; 11 — 12, anastomosing nerves to the fins; 9 — 10, anastomosing nerves, the 



function of which remained unknown to me. 

 F'ig. 126. Clionopsis uiicrocephalus n. sp. Ventral view. 4 X. 

 Fig. 127. The same, from the left. 4 X- 

 Fig. 128. Radula of the same. 



Fig. 129. Notobranchaea inopinata Pels. Ventral view. 10 X. 

 Fig. 130. The same specimen. Dorsal view. 10 ■ . 

 Fig. 131. Head of the same, dorsal view, be, buccal cones. 



Fig. 132. Oral aspect of the head; cephalic hood nearly closed. //, labial tentacle. 

 Fig. 133. Foot of the same; /, tubercle. 

 Fig. 134. Dorsal crest of the gill of the same. 

 Fig. 135. Radula of the same. 



