Zoological Society. 71 
shaped vesicles which open into the efferent duct of the ovary in 
Holothuria tubulosa, and which Delle Chiaje regards as testes, posi- 
tively showed no spermatozoa in three individuals, in which the pale 
rose-red ovary was otherwise much developed, and presented the 
most beautiful ova, with germinal vesicle and germinal spot. But 
in the first individual which my friend Professor Valentin opened, 
the organ corresponding and very similar to the ovary immediately 
presented a difference (from the ovary) in its white contents. We 
also saw indeed in those contents the most beautiful spermatozoa, 
much resembling these of osseous fishes. Numerous other individuals 
constantly presented themselves, either as males or females. 
“Regarding the Meduse, Von Siebold of Dantzic had already 
mentioned that he had found male individuals with spermatozoa in 
Medusa aurita. In Nice I convinced myself with the greatest cer- 
tainty in Pelagia, Aurelia, Cassiopeia, and a fourth genus, that these 
Meduside are always of disjoined sex. The males, with their sper- 
matozoa actively moving (even within the capsules of the testes), are 
at the first glance to be distinguished from the females, whose ovaria 
always contain ova in different stages of development*. 
“< It is of especial interest to find that a disjunction of sex admits 
of demonstration, even in the Polyps. One of my companions, Dr. 
Erdl, (?) of Munich, found in Veretillum only female individuals in 
one Polypary, and in others only males. He writes me that he has 
afresh convinced himself of the same relation in dlcyonium, though 
the specimen had been preserved in spirit; and that among the Mol- 
lusca he has found similar sexual differences in Halyotis ; thus in the 
Aspidobranchia of Cuvier. 
“<I must here remark, that my earlier statements on the sperma- 
tozoa of the Actinie are.erroneous, since I regarded entirely peculiar 
and remarkable capsules with long threads (situated even on the 
prehensile oa as spermatozea. 
“« My researches on the spermatozoa_of cartilaginous fishes have 
shown the remarkable fact that the individual genera of the Rays and 
Sharks are distinguishable by the form of their spermatozoa. ‘These 
spermatozoa are for the most part spirally wound, as in birds of song. 
Very remarkable is the structure of the testis ; which is constantly 
connected with a largely developed and winding vas deferens. That 
which Johann Miller has described in the Rays as a peculiar gland 
is nothing else than this vas deferens. 'The relations in form of the 
male genital organs alternate much, as I shall show in a special and 
more comprehensive work. 
«* The facts here reported were not witnessed by myself alone, but 
also by Professor Valentin of Bern, Dr. Peters of Berlin, and five 
young zootomists, pupils of mine, who were all in Nice at the same 
time as myself, and took a part in my observations.” 
* I shall state these sexual relations in a special and detailed work on 
the whole anatomy and physiology of the Meduse. 
