PLATE VII. 
Figs. 1- 6. Onchidium tonganum, Quoy et Gaimard. 
Fig. 1. Vertical section through longitudinal axis of fore end of foot; a, fore end of foot; b, orifice 
of foot gland. 
Fig. 2. Upper side of foot, from body cavity; a, mouth tube; b, foot gland; behind this the trans- 
verse muscular layer of foot, with entering nervi pedisei and opening of a vessel ; c, c, 
longitudinal layers ; cl, muscles descending from the sides of the body. 
Fig. 3. a, Prseputium, opened and showing glans; bb, vas deferens; c, musculus retractor penis. 
Fig. 4. End of glans penis ; a, orifice at the point. Cam. luc. x 350 diam. 
Fig. 5. a, Dart-cone opened ; b, end of the duct of dart-gland; c, dart; d, nerve: e, retractor muscle. 
Fig. 6. Dart ; a, termination ; b, base ; c, duct. Cam. luc. x 100 diam. 
Figs. 7-12. Onchidium verruculatum, Cuvier. 
Fig. 7. Posterior end of body ; a, pneumostome ; b, anal papilla ; c, vulva ; d. genital furrow. 
Fig. 8. Anterior end of foot from body cavity; a, mouth tube; b, foot gland; c, transverse mus- 
cular layer of foot. 
Fig. 9. Portion of rhachis of radula ; a, a, three median teeth ; b, b, first lateral teeth.. Cam. luc. 
X 350 diam. 
Fig. 10, End of a lobule of salivary gland. Cam. luc. x 55 diam. 
Fig. 11. End of ( d ) duct of dart-gland ; a, dart-cone; b, dart; c, base of dart. Cam. luc. x 100 diam. 
Fig. 12. End of dart ; a, opening at its extremity. Cam. luc. x 750 diam. 
Figs. 13-22. Bornella eoccepta , Bergh. 
Fig. 13. Anterior end of animal, from the side ; a, mouth ; b, tentacles ; c, anterior part of rhinophore 
with club and sheath ; cl, papillary part. 
Fig. 14. The club of the rhinophore and its sheath, from above ; a, part connecting it with the papil- 
lary part. 
Fi g. 15. Part of the labial disk ; a, fore-end of the rods. Cam. luc. x 750 diam. 
Fig. 16. Three lateral teeth of anterior incomplete series. Cam. luc. x 350 diam. 
Fig. 17. Lobule of hermaphrodite gland ; a, duct. 
Fig. 18. Anterior part of the penis ; a, orifice of seminal duct. 
Fig. 19. Posterior part of the same. 
Fig. 20. Constriction (a) between (c) prostatic and ( b ) muscular part of the vas deferens. 
Fig. 21. Part of the margin of the penis. Cam. luc. x 100 diam. 
Fig. 22. A single spine from the penis ; a, base. Cam. luc. x 350 diam. 
