252 
W. M. Wheeler 
ses dimensions considérables , n'obstrue pas complètement le tube 
digestif de la cornatale. « 
V. Graff says nothing about the sex of the specimen whicb he 
examined. Prouho however distinctly affirms that 31, pulmnar is 
dioecious, with a »dimorphisme sexuel bien accentuécf. The speci- 
men which V. Graff described corresponds to' the female of Prouho. 
The male is thus described by the French author: »Le male ne 
mesure que 1 mm de longueur sur 0.8 mm de largeur; il est accroché 
aux téguments de la femelle sur laquelle il peut se déplacer assez 
rapidement. II est aplati, elliptique, rappelant par sa forme les 
Myzostomes libres. Son tube digestif n'est pas ramifié, mais montre, 
de chaque coté, les amorces des trois ramifications que presentent 
tous les autres Myzostomes ; sa bouche, située tout prés du bord mar- 
ginal, est ventrale. II possedè deux testicules, un de chaque coté du 
tube digestif, munis chacun d'un canal déférent débouchant sur la 
face ventrale.« 
Prouho's remarks show unmistakably that M. pulmnar closely 
resembles some of the cysticolous species described by v. Graff 
[M. cijsticolum^ tenuispinum^ tvillemoesii^ etc.) in presenting large 
female and small male individuals. 
My own observations on this species are based on some 30 spe- 
cimens taken in the Bay of Sorrento. About half of these would 
correspond to Prouho's males, the remainder to bis females. The 
living females are of a beautiful coral red color, sometimes inclin- 
ing to yellowish; the males are white and somewhat translucent. 
I bave been able to confìrm Prouho's notes on the habits of this 
species in every particular. I bave, however, frequently seen the 
scoop-shaped posterior end of the female Myzostome protruding from 
the Crinoid's mouth like a little red tongue. 
The female specimens which came under my notice measured 
2.75—3.5 mm in length and 3.75 — 4.5 mm in breadth. One of these 
specimens is represented in dorsal and ventral view in PI. 12 Figs. 41 
and 42. Fig. 41 shows two males [juv] attached near the cloacal 
orifìce [an]^ which is situated on the dorsal surface, and another on 
the postero-lateral edge of the body. These males when magnified 
(Fig. 43; ventral view) appear like typical Myzostomes of another 
species. They measure 0.5—0.85 mm. In most cases only a single 
male is borne by a female. 
The associatìon of these Myzostomes in pairs at once recalls the 
similar conditions in M. glahrum and M. alatum^ and although the two 
