318 
Miscellaneous. 
spined embryos have made their way, or even when they are set 
free in the peritoneal cavity (in the wild rabbit), continue their 
metamorphoses in situ, and arrive at the adult sexual state without 
quitting the organism into which they penetrated as a microscopic 
ovum (only 0030-0070 millim. in diameter); only, in this case 
they furnish an unarmed Tania. On the other hand, if the same 
vesicular worm is swallowed by a Carnivore or an Omnivore, it 
becomes, in the intestines of the latter, an armed Tania ; that is to 
say, it retains the hooks of the scolex from which it originates. 
In the former cases it loses them. 
He adds that certain unarmed and armed Tania are therefore 
two adult and parallel forms of the same worm ; and the differences, 
often very great, which they present (as in the case of Tania per- 
foiliata of the horse, and Tania echinococcus or T. nana of the dog, 
which originate from the same vesicular worm) are due exclusively 
to the difference of habitation and medium in which their final 
metamorphoses have been accomplished.— Comptes Benches, January 
13, 1879, p. 88. 
On the Segmental Organs and Genital Glands of the Sedentary 
Polychatal Annelids. By M. L. C. E. Cosmovici. 
Although many naturalists have paid attention to the organiza¬ 
tion of the Polychietal Annelids, it still remained to be ascer¬ 
tained in this group what is to be understood by the term 
segmented organ, and what is the nature of the organs of repro¬ 
duction. Researches carried on for two years at Roscoff and at the 
Sorbonne, in the laboratories of experimental zoology of H. Lacaze- 
Duthiers, have led me to the following results. 
The glandular sacs found in the interior of the body in these 
animals, and regarded by many authors as genital glands, were taken 
by Claparede, Iveferstein, Ehlers, and others for segmental organs. 
Now their organization is more complex. 
In a certain number of sedentary annelids, such as Arenicola, 
Terebella nebulosa, and others, these sacs are composed of two very 
distinct parts—one glandular, with very vascular walls, opening 
outwards by a special pore, and in the interior of which we detect, 
by means of reagents, a great number of crystals which appear to 
be formed of uric acid ; this is incontestably a urinary organ or a 
corpus Bojani ; the other part, which is not granular, is composed 
of a pavilion with two lips, more or less provided with very ciliate 
fringes, followed by a tube which is applied to the surface of the cor¬ 
responding corpus Bojani. A communication exists between the two 
parts in the point of attachment; so that all bodies collected by the 
pavilion of one of these organs passes into the corpus Bojani, and is 
afterwards carried by the ciliary current towards the external open¬ 
ing. It is to the second part of these sacs that tbe name of segmental 
organ must be given. 
The distinction between these two parts is observed with the 
utmost clearness in a great number of sedentary annelids. Thus in 
Terebella conchilega there are three pairs of these pouches which 
