Fig. 4 in Cutting the ribbon: bathyal Nemertea from seeps along the Costa Rica margin, with descriptions of 2 new genera and 9 new species

Fig. 4. Tubulanus cf. lutescens Cantell, 2001 (SIO-BIC N277), transverse histological sections. A. Anterior region of head with proboscis pore. B. Posterior brain region with mouth opening and buccal nerves (arrowheads). C. Proboscis composition and the two proboscis nerves (arrowheads) in the foregut region. D. Brain region showing the cerebral canal. E. Body wall composition in the foregut region, arrowhead indicates upper dorsal nerve. F. Lateral nerve cord in the foregut region. Abbreviations: br = brain; cc = cerebral canal; cl = cephalic loop; dl = dorsal brain lobe; e = epidermis; es = esophagus; icm = inner circular muscle layer; lb = lateral blood vessel; lm = longitudinal muscle layer; ln = lateral nerve cord; mo = mouth opening; ocm = outer circular muscle layer; p = proboscis; pcm = circular musculature of proboscis; pcn = precerebral nerves; pe = proboscis epithelium; plm = longitudinal musculature of proboscis; pp = proboscis pore; rc = rhynchocoel; rcm = circular musculature of rhynchocoel; vc = ventral commissure; vl = ventral brain lobe. Scale bars: A–C, E = 200 µm; D, F = 100 µm.