538 



FLOKENCE BUCHANAN. 



The other species in which the spiral arrangement is so 

 common is one of which Cori also examined a specimen^ and 

 he remarks on the large number of so-called abnormalities in 

 it, though he only describes two cases of intercalation. This 

 species is Hal la Parthenopeia, Of the two specimens of 

 it in the Zoological Museum here (both of them from Naples), 

 one has eleven and the other twelve distinct asymmetrical 

 parts, the nature of which and their relation to the whole 

 length of the animal will be seen in the following table : 



The same specimen has a half-segment intercalated between 234tli and 235th 



segments on left side. 

 „ „ „ piece intercalated on the dorsal surface on right side 



of the 383rd segment. 

 ,, „ „ half-segment on the right side and two pieces in the 



mid-dorsal line intercalated between 501st and 



502nd segments. 



' See foot-note, p. 537. 



