BALAN0GL0SST7S OTAGOENSIS. 503 



laid on the variations presented by tiie different genera, it 

 seems worth while to note the peculiarity in the present 

 species. 



EXPLANATION OF PLATE 45, 



Illustrating Mr. Blaxland Benham^s paper on "Balano- 

 glossus otagoensis, n. sp.^' 



Fig. 1. — Dorsal view of Balanoglossus otagoensis (x 8) from a 

 sketch of the living animal ; the gill-pores have, however, been inserted from 

 later study, (a) The characteristic groove on the proboscis. 



Fig. 2.— "View of the left side of the specimen after staining and clearing. 

 The depth of the groove (a) is indicated, (b) The " cardiac vesicle." (c) 

 Branchial region, (d) Genital region. 



Fig. 3.— Sketch of gill-bars. 



Fig. 4. — Half a transverse section through the region of the collar-pore, to 

 show the end of the subnotochordal skeleton, x 125. (a) Dorsal nerve-cord. 



(b) Dorsal blood-vessel, (c) First gill-sac. (d) Collar funnel and pore opening 

 into it. (d) Parts of gill-bar. (e) Pharynx, (f) Limb of subnotochordal 

 skeleton, (g) Longitudinal muscles, (h) Collar cavity (camera). 



Fig. 5. — A transverse section of the proboscis near the anterior end (stained 

 with picro-carmine). X 125 (camera outline), (a) Epidermis, (b) Nerve tissue. 



(c) Basement tissue, (d) Longitudinal muscles, confined to a very narrow 

 area, (e) Connective tissue, (r) Cavity of proboscis, (g) Dorsal groove. 



Fig. 6. — Outline of transverse section of proboscis (camera) near the middle. 

 X 125. 



Fig. 7. — Transverse section of proboscis near the base (camera), x 125. 

 (a), (c), (d), (e), (f), as before, (g) Central sinus, (h) Cardiac vesicle, 

 (i) Glomerulus, (j) Notochord. 



Fig. 8. — A portion of the section of the wall of the proboscis in the region 

 of the square on Pig. 5. X 450 (drawn with camera), (a) Epidermis, (b) 

 nerve layer, (c) Basement tissue and circular muscle, (d) Longitudinal 

 muscle-fibres, (e) Connective tissue with nuclei. 



Figs. 9, 10. — Two transverse sections of the " basal complex " to illustrate 

 modifications in form of cardiac vesicle, (g), (h), (i), (j), as in Fig. 8 (both 

 drawn with camera). X 150. 



