SEGMENTATION OP CERTAIN POLYCH^TES. 543 



EXPLANATION OF PLATE XLII, 



Illustrating Miss Florence Buchanan's paper on ''Peculiarities 

 in the Segmentation of certain Polychsetes/' 



Fig. 1. — Six segments of an Amphinome (Madras Collection, No. 5), of 

 which three form a simple right-handed spiral, beginning and ending on the 

 dorsal surface. Dorsal view. Enlarged. 



Fig. 1 A. — Ventral view of the same segments. 



Fig. 1 B.~Diagrammatic representation of the spiral. 



Fig. 2. — Six and a half segments of an Amphinome (Madras Collection, 

 No. 6), of which three and a half form'a left-handed spiral, beginning on the 

 dorsal and ending on the ventral surface. Dorsal view. Enlarged. 



Fig. 2 a. — Ventral view of the same segments. 



Fig. 2 b. — Diagrammatic representation of the spiral. 



Fig. 3. — Ten segments of an Amphinome (British Museum Collection, 

 No. 2i) in which there are two right-handed spirals, one inside the other. 

 Dorsal view. Enlarged. 



Fig. 3 a. — Ventral view of the same segments. 



Fig. 3 b. — Diagrammatic representation of the spirals. The longer one is 

 represented as though lined with black, the smaller one as though with a 

 shaded lining. 



Fig. 4. — Five segments of an Amphinome rostrata (British Museum 

 Collection, No. 3), showing a condition intermediate between normal and 

 spiral segmentation. Dorsal view. Enlarged. 



Fig. 4 b. — Diagrammatic representation of the same. 



Fig. 5. — Incomplete posterior end of an Amphinome rostrata (British 

 Museum Collection, No. 16), showing segments intercalated on the right side 

 causing the body to coil to the left. Dorsal view. Enlarged. 



Fig. 5 a. — Ventral view of the same. 



Fig. 6. — Six segments of a Halla Parthenopeia (in U. C. L. Museum, 

 No. 2), showing two small spirals inside one larger one. Enlarged. 

 Fig. 6 a. — Ventral surface of same. 

 Fig. 6 b. — Diagrammatic representation of the spirals. 



