456 A. E. Verrill — Marine JSTemerteans of New England. 



Figures 10, 11, 12. — Ce-phalotlirix linearis. Different stages in the development of the 

 larva, much enlarged ; c, large cephalic cilia; a, region of the mouth; ft, intes- 

 tinal area. After Mcintosh. 



Figure 13. — The same, farther developed; o, oceUi, li, ganglions; a, mouth area; rf, 

 opening of cephalic ducts; m, ,one of the cephalic sacs; /, oesophagus; p, pro- 

 boscis ; h, intestine, imperfectly developed. After Mcintosh. 



Figure 14. — Cephalothrix linearis. Head, much enlarged, and seen as a transparent 

 object ; m, mouth ; p, proboscis ; p\ rhynchodeum ; v, proboscis-sheath ; h. 

 lateral blood vessel; g, superior, r/', inferior gangUon ; n, origin of lateral nerve. 

 After Mcintosh. 



Figure 15. — The same. Part of a transverse section of the body-wall adjacent to one 

 of the lateral nerves ; c, external cuticle layer ; c% basement layer ; t, outer, and 

 t\ inner circular muscular layers; /, longitudinal muscular layer; ?i, lateral 

 nerve. After Hubrecht. 



Figure 16. — Car inina grata Ji. Section of a part of the body-wall corresiDonding to 

 that in the preceding figure with the same lettering. After Hubrecht. 



Figure 17. — Cerebrafulus niedtdlatus H.nhr. Section of the body-wall in the region of 

 the median dorsal line; lettering the same as in the two preceding figures, with 

 the following additional ones; nd, median dorsal nerve ; n, nervous plexus; n", 

 proboscis-nerve; V, inner longitudinal muscular layer. After Hubrecht. 



Figure 18. — Lineus viridis. Transverse section through tlie middle of the body; 

 X 14; j), proboscis ; v, proboscis-sheath; h, dorsal blood vessel ; ?/, one of the 

 lateral blood vessels; /, cavity of intestine ; c, external cuticular layer; c', base- 

 ment layer of cuticle ; I, outer, and I', inner longitudinal muscular layers ; t, 

 circular muscular layer ; t', transverse muscular bundles arising from t; n. ner- 

 vous plexus ; n% lateral nerve ; ro, reproductive organs. After Mcintosh. 



Figure 19. — Cerebratulus lacteus. Transverse section of the middle region of the 

 body; x 8. Lettering the same as in figure 18. From nature by the author. 



Figure 20. — The same. Transverse section in the region of the oesophagus ; x 8. 

 Lettering the same as in figures 18 and 19, with the following additional ; ?', 

 plicated wall of the oesophagus; n" , median dorsal nerve; ?<, ■«, nephridia. 

 From nature, bj^ the author. 



Figure 21. — The same. Portion of the same section shown in figure 20, from the 

 region of the lateral nerve; x 3G. Letters the same as in figures 18 and 20. 

 From nature, by the author. 



Figure 22. — Lineus viridis. Head and anterior part of body viewed as a transparent 

 object; o. ocelli; /./.lateral cephalic slits; g, superior ganglion; cf, interior of 

 olfactory sac; d', its duct; n', lateral nerve; ?«, mouth; e, oesophagus; p, pro- 

 boscis ; p\ rhynchodeum ; v, proboscis-sheath ; r, r, blood lacunae surrounding 

 the oesophagus. After Mcintosh. 



Figure 23. — Malacobdella mercenarice. Dorsal view; x 4. Newport, R. L, July, 

 1880, in Venus mercenaria. J. H. Emerton from life. 



Figure 24. — Tetrastemma dorsale. Central .stylet; x 200; 24«, one of the lateral 

 stylets; x 350. After Mcintosh. 



Figure 25. — Tetrastemma cCmdidum. Central stylet ; x 150. After Mcintosh. 



ERRATUM. 



Page 384, line 23, for Nemertinea, read Nemertina. 

 Page 405, line 31, for Candida, read candidum. 



