Messrs. Hancock awe? Embleton on the Anatomy o/Eolis. 97 
gentleman^s account of the genital organs of his Eolidina, we find 
it to be very meagre and imperfect. He states at the commence- 
ment that these are as simple as possible ; we have found them to 
constitute that part of the organization which is the most com- 
plicated and difficult to be understood. The copulative vesicle 
he mentions_, which he thinks analogous to that of insects, and 
destined to receive and preserve the spermatic fluid of the same 
individual, acting the part in fact of seminal vesicle, and which 
he is tempted to believe renders the conjunction of two individuals 
unnecessary, seems to correspond to the spermatheca : the only 
other parts he mentions, the testis and ovary with their ducts, we 
find great difficulty in identifying with the parts described as 
such in our paper. That the congress of two individuals does 
really take place, we have had abundant proof. 
In the latter gentleman^s paper on Tergipes above-quoted, we 
have a confused but more detailed account of these organs. The 
Professor seems to have confounded the testis and ovary together, 
owing to the action of the compressor ; for we cannot believe in 
the development of spermatozoa in the female parts, and in this 
we agree with his translator as well as in our conviction that the 
“ poches seminales ” are parts of a multiple testis. If this be the 
true interpretation then, we find that in this section of the genus 
there is a modification of the testis which does not exist, as far as 
we know, in any of the others. Such a modification we think 
not improbable, since we have observed a similar conformation in 
Chalidis, a naked mollusk having considerable affinity to the 
Eolididee, and placed as the lowest genus in M. de Quatrefages’ 
order Phlebenterata. The liver, as M. de Nordmann gives it, ap- 
pears to be a part of the large mucus-gland we have described. 
The urinary gland is perhaps the opake granular part of the 
same. The testis is evidently the spermatheca, from its form and 
contents. The vessie muqueuse” would seem to answer to the 
sac of the penis, and the short flexuous canal, which, coming from 
the crytalloid (?) bodies of the foot, enters its posterior extremity, 
appears to indicate the duct of the true multiple testis. 
Organs of Circulation. 
These are a heart and blood-vessels. 
The central organ consists of auricle and ventricle with valves. 
The vessels are arterial and venous. 
The heart and the roots of the large vessels lie in the wide 
ca\ity of a delicate pericardium, PL IV. figs. 2 and 4//, c c ; this 
is a very fine transparent membrane, difficult of detection at first, 
which is attached to the aorta just beyond its origin, and to the 
three great venous trunks just before their union in their com- 
mon sinus, the auricle. At the same parts its external surface is 
Ann. ^ Mag. N. Hist. Ser. 2. Vol. i. 7 
