68 NEW YORK STATE MUSEUM 



tip. What may be termed the inferior appendages are not dis- 

 tinctly separated from the side pieces, and consist of a ventral 

 plate apparently deeply slit; seen from the side the separate 

 divisions of the plate appear as a rather long appendage slightly 

 upturned and blackened at the point. The penis is club-shaped 

 at the apex in one aspect; in another it is slightly excised at the 

 apical margin and the club is hollow with a slender rod-like 

 process lying within it. The penis seems to be formed of two 

 joints, the apical jirobably capable of being partly retracted 

 within the other; the latter joint is broad at the proximal part, 

 but becomes constricted before the apex; a spiral sheath arises 

 from about the middle of the organ. Beneath the penis is a 

 transparent process out of which proceed two or more spines, and 

 on either side of this central process are sometimes visible two 

 minor ones. 



There is some uncertainty about the form of the dorsal plate, 

 but the true form of this will be readily ascertained from prepara- 

 ations made from fresh or dried specimens. Equally there is 

 uncertainty about the cleavage of the ventral plate. These trans- 

 parent menifbranous plates appear to suffer in form from immer- 

 sion in alcohol. 



A species closely allied to I. lamellaris of Europe, of 

 whose appendages no adequate figures have so far, been published. 

 Tn I. lamellaris in the part corresponding to that which is 

 called above " inferior appendages " there is, I believe, no slit, 

 although a long, narrow part where the membrane is thinner 

 sometimes gives nn illusory idea of a slit. In lamellaris 

 the dorsal plate is produced in the centre with a blunt, slightly 

 rounded lobe, while the process underneath the penis is about 

 equal in breadth to the above-mentioned lobe, and instead of 

 l)eing simple as in c 1 a v n t a it is subdivided Ivy an excision. 



The larva referred to in P.^j/rhr, vol. ix, pp.37.5-8, is almost cer- 

 tainly that of the species just described. Whether the views ex- 

 pressed in that paper are well founded or not can only be 

 determined by a more complete knoAvledge of the life history of 

 the creature, the working out of which sliould be sufficiently at- 

 tractive even if it does not result in the verifiration of Professor 

 Needham's views. 



