1905.] GEPHYREAX WORMS OF ZANZIBAR, ETC. 31 



9. Physcosoma evisceratum, sp. nov. (Plate I. fig. 1.) 



Log. Chwaka, Zanzibar. 



There is only a single specimen present, in which all the 

 internal organs, including even the muscle-layers, have entirely 

 disappeared. The part of the introvei't that bears the tentacles 

 is also broken away. But the hooks and papillae present features 

 which prevent me from placing the specimen in any known 

 species. 



The introvert is as long as, or a little longer than, the body ; 

 it is not possible exactly to mark the limit between the two, so 

 that perhaps, I'oughly speaking, it is better to describe them as 

 equal in length, the introvert being at any rate not shorter than 

 the body. Both are covered entirely, except for a small piece 

 at the extreme anterior end of the introvert, with large conical 

 papillae, which are largest at the extreme hind end and smallest 

 in the middle of the body ; generally colourless, at irregular 

 intervals over the body a single papilla appears dark-brown and 

 very distinct as against its surroundings. The appearance of the 

 papillae under the microscope is shown in PI. I. figs. \a k \h ; 

 those from the hind end are characteristically raised, in their basal 

 regions, into small secondary papillae. 



The rows of hooks are numerous. In the region behind the 

 mouth I find 15 rows (but these may in reality be more numerous, 

 allowing for the teai^ing above mentioned) ; then comes a narrow 

 interval, and again some 15 rows of hooks, and then after a 

 similar interval 30 rows. All the hooks are alike in structure ; 

 fig. 1 G gives a representation of one, and the characteristic feature 

 to which I wish to draw attention is the presence of a distinct 

 process projecting from the dai-k curved line bounding the convex 

 border of the light central area and encroaching on the latter. 



Finally the body, which is markedly broader than the introvert, 

 is unpigmented save for the isolated papillae mentioned above ; 

 while the introvert is more or less brown, the coloration tending 

 to be concentrated along a line that is probably either mid-dorsal 

 or mid-ventral ; only the narrow areas which separate the three 

 areas of hooks are whitish. 



III. Genus Phascolosoma. 



10. Phascolosoma semperi Sel. & de Man. 



Selenka, torn. cit. p. 37. 



Log. Chwaka Bay ; two specimens. 



On one of these Mr. Orossland has the following note: "Opaque 

 white skin like fine sand -paper in appearance." 



11. Phascolosoma vulgare Blainv., var. nov, selenk^e. 

 (Plate I. fig. 2.) 



Of. Selenka, toTn. cit. p. 23 (1883) ; and var. tro'picttm Sluiter, 

 Siboga-Exp. p. 33 (1902). 



