REVISE THE GROUP AND TO DETERMINE ITS GEOGRAPHICAL RANGE. 345 



Genus IV. SACCOSOMA. Koren and Danielssen. 



From " <ratcico<; = sack, crio/jia = body." 



Species 10. Saccosoma vitreum. Koren and Danielssen. 



Koren and Danielssen. The Norwegian North Atlantic Expedition: Zoology, 

 Gephyrea, Christiania, 1881, p. 34. 



Described from a single specimen. 



Length of body, 3 cm., 5 mm. broad. Proboscis absent. 



Colour, white shot with .red anteriorly and posteriorly, the middle of the body is 

 colourless. 



Skin anteriorly and posteriorly thick and rugose, but thin and transparent round 

 the centre of the body. 



Longitudinal muscles in numerous bundles — but the number is not stated — in the 

 anterior part of the body ; they fuse into a continuous sheath, about half-way down the 

 animal. 



Nephridium, single, that of the left side. 



The material inside the intestine is arranged in pellets. 



Anal trees, not found. 



Locality. Dredged at a depth of 1215 fathoms, about half-way between Iceland 

 and Norway, from a bottom of "sabulous clay." 



Genus V. THALASSEMA (Gaertner). Lamarck. 



Pallas in his "Spicilegia" mentions the name Thalassemia as used by Jos. Gaertner. 

 but he himself calls the animal in question Lumbricus thalassemia. It would seem that 

 Lamarck in his Systeme des Animaux sans Vertebres, 1801, p. 328, was the first to use 

 the word Thalassemia generically. His statement that the word is used in Cuvier appears 

 to be erroneous. It is in full use in the edition of Buffon, Vers. I. 1802, p. 225. 



I am indebted for the above particulars to the kindness of Mr Davies Sherborn. 



Species 11. Thalassemia baronii. Greef. Plate XXXIII. Figs. 1 and 7. 



Greef. Acta Ac. German, Vol. XLI. Pt. ir. 1879, p. 151. 



Shipley. "Notes on a Collection of Gephyrean Worms formed at Christmas 

 Island by C. W. Andrews," P. Zool. Soc. London, 1899. 



Length of body, 7—8 cm. Length of proboscis, 5—6 cm. 



Colour, dark green, with violet longitudinal stripes, and with white specks— papillae 

 —irregularly scattered all over the body. The dorsal side of the proboscis is light green, 

 the ventral is of a brownish flesh colour. 

 Longitudinal muscles, 17 — 19 bundles. 



47—2 



