ON SOME SOUTH PACIFIC NEMERTINES COLLECTED BY DR WILLEY. 



581 



EXPLANATION OF LETTERS USED IN PLATES. 



a.c anal commissure 



b.m basement membrane 



b.v lateral blood vessel 



c.c cerebral canal 



cer cerebrum 



c.org cerebral organ 



cv cutis 



cu.gel gelatinous layer of cutis 



d.b.v dorsal blood vessel 



d.c dorsal commissure 



d.c.ant anterior dorsal commissure 



d.c. post posterior dorsal commissure 



d.g dorsal ganglion 



d. n dorsal nerve 



d.v dorsal blood vessel 



ep epidermis 



ep.h.f. epithelium of head furrow 



ex.bl excretory ' ' bladder ' ' 



ex.d excretory duct 



ex.gl excretory gland 



ex.p excretory pore 



ex. t excretory tubules 



g.c ganglion cells 



gl glandular portion of cerebral organ 



gl.c composite epidermal glands 



gl.d deeper cutis glands 



gl.p proboscis pore glands 



h.f. head furrow 



h.g head glands 



h.s head slit 



int intestine 



int. d intestinal diverticulum 



m mouth 



m.c circular muscle layer 



m.ci internal circular muscle layer 



m.d.v dorso-ventral muscles 



m.g mid-gut 



mg.gl glandular tissue of mid-gut 



m.l longitudinal muscle layer 



m. I. ext external longitudinal muscle layer 



m. I. int internal longitudinal muscle layer 



m. I. oes longitudinal muscle layer of oesophagus 



m.l.p.s longitudinal muscle of proboscis sheath 



n. c lateral nerve cord 



n.cl nerve cells 



n.c.org nerve to cerebral organ 



n.l nervous sub-epidermal layer 



n.oc nerves to eyes 



n.oes oesophageal nerve 



oc eye 



oc.d dorsal eye 



oc.v ventral eye 



oes.t oesophageal "typhlosole" 



ov ovary 



ov.d dorsal portion of ovary 



ov.v ventral portion of ovary 



p proboscis 



par parenchym 



p.ep proboscis epithelium 



pg.m pigmented mass of cerebral organ 



p.n proboscis nerve 



p.p '....proboscis pore 



p.s proboscis sheath 



ps.gl glandular thickening of proboscis sheath 



TCt proctodaeum 



rh rhynchocoelom 



rh.d rhynchocoelom diverticulum 



r.gl rhynchodaeal glands 



V. b.v ventral blood vessel 



v.c ventral commissure 



v.c.ant anterior ventral commissure 



v.c. post posterior ventral commissure 



PLATE LVII. 



Fig. 1. Carhiesta orientalis. Sketch of anterior extremity, after preservation, x 6. 



Fig. 2. C. orieyitalis. Schematic reconstruction, from a series of sections, shewing the 

 arrangement and relations of the nervous, vascular, and excretory systems. 



Fig. 3. C. orientalis. Section through precerebral region, x 110. 



Fig. 4. C orientalis. Section through brain, x 110. 



Fig. 5. C. orientalis. Section through mouth region, x 60. 



Fig. 6. C. orientalis. Schematic representation of the arrangement of the various muscle 

 layers shortly behind tlie mouth. 



77—2 



