SCIENTIFIC SUMMARY. 
93 
resides in the same host in two stages of its development — namely, as the 
true cystic worm in the visceral cavity of the Glomeris; and in the scolex 
state, encysted in the adipose tissue of the same animal. M. Villot describes 
the parasite as consisting of three distinct parts, which he calls head, body, 
and caudal vesicle. The head is oval, truncate in front, and furnished with 
four sucking discs, and with a long trunk. The latter is invaginated in the 
head, which in its turn is invaginated in the body, and this again in the 
caudal vesicle. The invagination of the trunk forms a funnel-like hollow at 
the apex of the head, and the inner wall of the latter is armed with a circlet 
of excessively minute hooks, ytuv inch long. 
The multiplication of the worm in the cystic stage is effected (as we 
understand the statements of the author) by budding at the posterior extre- 
mity of the caudal vesicle, and the buds are usually thrown off as soon as 
they are perfectly formed, so that the colony rarely consists of more than 
two individuals. The scolex formed in the hud, which remains during its 
final development attached to the parent worm by a thin pedicle, seems to 
resemble that of the parent in all respects; when detached it speedily 
throws off the enclosing vesicle, and proceeds to encyst itself in the adipose 
tissue of the host, still invaginated in the so-called ‘body.’ The further 
development of this worm is still unknown ; it probably takes place in some 
Alpine bird or mammal, the cystic worms having been obtained from a 
Glomeris collected in the woods of the Grande Chartreuse. 
The Discomedusce. — Prof. Hackel has read before the Medical Society of 
Jena a memoir on the organization and classification of the Discomedusae, a 
group which he defines as including all those Acraspeda which, in their 
youth pass through the well-known ontogenetic larval form of Ephyra 
( Ephyrula ), as represented by the first free-swimming product of the division 
of the so-called Hydra tuba. These may be regarded in accordance with the 
‘ biogenetic fundamental law,’ as all phylogenetically derivable from an original 
common stock-form, resembling JEphyra : Ephyrcea. — This common starting- 
form of all Discomedusae possesses eight sense-organs (4 per-radial and 4 inter- 
radial), and alternating with these 8 adradial tentacles, and intercalated 
between the former and the latter 16 marginal lobes. The umbrella of all 
Discomedusae is shallow and discoidal, and their sexual glands are developed 
by centripetal growth in the subumbral stomachal wall. The great number 
of new Discomedusae which the author has had the opportunity of examining 
during the last few years have led him to form a new classification of the 
group. He distinguishes in it three sub-orders and ten families, characterized 
as follows - 
Sub-order 1. — Cannostom^e (Tubular-mouthed Medusae) : Mouth-tube 
simple, without buccal tentacles. Central mouth simple, square. Radial 
pouches, without an annular canal. Either 4 or 8 gonads (reproductive 
organs). Tentacles solid, usually short. 
Families. — 1. Ephyeid-® : Radial sacs broad, simple, without ramified 
distal canals, without an annular canal. — Subf. 1. Palephyrida, with 8 sense- 
organs and 8 tentacles, with 4 horseshoe-shaped interradial gonads. — Genera, 
Ephyra, Palephyra, Zonephyra. — Subf. 2. Nausithoidce, with 8 sense-organs 
and 8 tentacles, and 8 separated adradial gonads. — Genera, Nausicaa, Hausi- 
thoe, Nauphanta : Subf. 3. Collaspidce, with from 16 to 32 sense-organs, and 
