REVISE THE GROUP AND TO DETERMINE ITS GEOGRAPHICAL RANGE. 349 



Species 20. Thalassema kokotoniense. Fischer. Plate XXXIII. Fig. 3. 

 Fischer. Jahrb. Hamburg. Anstalt, ixth year. Pt. II. 1891, p. 82. 



Described from a single specimen. 



Length of body, 4"2 — 4*5 cm. Greatest diameter, 17 cm. The hinder part of the body 

 is the broader. Proboscis absent in Fischer's specimen but present in mine, and 1"2 cm. 

 long. 



Colour, light green, rather bluish, becoming darker posteriorly. 



Papillae, distributed all over the body, smaller anteriorly, arrange) 1 in more or less 

 definite transverse rows, which are interrupted by rings of larger papillae. The larger 

 posterior papillae are reddish. 



Longitudinal muscles, 17 — 18 bundles. 



Nephridia, three pairs, with spirally twisted internal openings. 



Anal trees, with well-marked funnels. 



Locality. Kokotoni, E. Africa; and Blanche Bay, New Britain. 



Species 21. Thalassema lankesteri. Herdman. 



Herdman. Quart J. Micr. Sci. N.S. Vol. XL, 1898, p. 381. 



Described from three large fragments. 



Length of body about 10 cm., the proboscis nearly as long as body. 

 Colour, in the living animal, apple or chrome green on the trunk, lighter on the 

 proboscis. 



The skin evenly tuberculated all over. 



Longitudinal muscles, continuous. 



Nephridia, one pair, with spirally twisted internal openings. 



Anal trees, branched, with funnels at tips of branches. 



Locality. Off the Isle of Man, 50 fathoms. From a stiff blue mud bottom. 



Species 22. Thalassema leptodermon. Fischer. 



Fischer. Jahrb. Hamburg. Anstalt, ixth year. Pt. II. 1891, p. 84. 



Described from three mutilated specimens. 



Length of body, 3-5 cm. Length of proboscis. To cm. Cylindrical body with a slight 

 constriction round the middle. 



Colour, yellow in spirit. 



Papillae," distributed all over the body ; they are biggest and thickest at a zone 

 near the hinder end, and are absent at the extreme posterior end. The skin is very 

 soft. 



Longitudinal muscles, 15 — 16 bundles. 



Nephridia, three pairs, with spirally twisted internal openings. 



Anal trees, of almost uniform diameter, with numerous funnels. The rectum bears 

 a spherical diverticulum. 



Locality. Zanzibar, Bueni Riff. 



