108 ON MYZOSTOMIDA FROM THE RED SEA. 



12. Maidl, F.— "Ueber die Coelomverhaltnisse von Mi/zosioma." 



Verh. zool.-bot. Ges. Wien, Bd. Ix. 1910, p. 200. 



13. McClendon, J. F.— "The Myzostomes of the 'Albatross' 



Expedition to Japan." Bull. Amer. Mus. Nat, Hist, 

 vol. xxii. 1906, p. 119. 



14. . " New Marine Worms of the Genus Myzosioma." 



tSmithson. Inst. U.S. Nation. Mus. Proc. vol. xxxii. 1907, 

 p. 63. 



15. Nansen, F. — " Bidrag til Myzostomernes Anatomi og 



Histologi." Bergen, 1885. 



16. Stummer-Traunfels, R. v. — " Beitriige zur Anatomie und 



Histologie der Myzostomen. I. Myzostoma asterue 

 Marenz." Zeitschr. f. wiss. Zool. Bd. Ixxv. Heft 4, 1903, 

 p. 49. 



17. Wheeler, W. M. — "The Sexual Phases of Myzostoma." 



Mitth. Zooi. Stat. Neapel, Bd. xii. Heft 2, 1896, p. 227. 



EXPLANATION OF THE PLATES. 

 Plate V. 



Figs, 1-6. Mi/zostoma costatum F. S. Leuckart. — Series of specimens illustrating 

 the variation in the shape of the body and the development of the costse. 

 The individuals shown in figs. 2 and 3 possess an abnormal number of 

 parapodia {cf. p. 93). In all the figures a represents the dorsal, h the 

 ventral aspect of the animal. X 12, 



Plate VI. 



Fig. 1. Myzostoma rubrofasciafum v. Graff. — Dorsal view. X18. 

 Figs. 2-3. Myzostoma crosslandi, sp. n. — Two specimens, dorsal and ventral aspects. 

 X12. 



Plate VIL 



Figs. 1-5. Myzostoma crosslandi, sp. n, — Transverse sections to show the anatomy. 



CM. Central nerve-mass. int. Branch of intestine. m. Muscular 



sheath. n. Nephridmm. o. Ovarj'. ov. Oviduct. r. Hectuni. 



sp. Mass of spermatozoa occupying coelomic space, st. Stomach. 



te. Testis, vt. Branch of the uterus. 

 Fig, 1, Section passing through the ovaries. 

 Figs. 2-4. Sections passing through the anterior portion of the oviduct and showing 



the position of the nephridia. 

 Fig, 5. Section passing through the posterior parts of the stomach and oviduct. 



Plate VIIL 



Fig. 1. 3Iyzostoma crosslandi, sp. n. — Photograph of a transverse section through 



the posterior region of the body, passing through the cloacal papilla 



{cl-ij.). Lettering as in Plate VII. 

 Fig. 2. Myzostoma costatum K. S. L. — Photograph of a longitudinal section showing 



the principal organs, ph. Pharynx. 

 Fig. 3. Myzostoma costatum F. S. L. Photograph of a transverse section passing 



through the anterior extremity of the stomach and showing the ring of 



glandular tissue {gl.) developed round the alimentary canal in this 



region. 

 Fig. 4. Myzostoma costatum F. S. L.— Part of the same section as fig. 2, under a 



higher magnilication, gl. Glandular tissue. 



