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SUMMARY OF CURRENT RESEARCHES RELATING TO 
is short, except in Carinoma ; the whole gut is lined by high ciliated 
epithelium, which fills'up the lumen during digestion; at the mouth 
there is sometimes a circle of salivary gland-cells. 
The gut has a distinct musculature — of longitudinal fibres on the 
fore-gut, of circular fibres on the mid-gut. Most Metanemertini (except 
Malacobdella and Pelagonemertcsy have a caecum, at the junction of fore- 
gut and mid-gut. 
Proboscis and rliynchocoelom are always present. The proboscis is 
fixed anteriorly by its whole surface to the wall of the rhynchoccelom ? 
posteriorly by two retractors (absent in Cerebratulus, according to Coe) ; 
it consists of a muscular sheath and a high internal epithelium with 
mucus-cells, rhabdites, and stinging-cells. In Metanemertini there is 
usually a stilet apparatus, including functional stilets and reserve stilets, 
which lie in pockets, each associated with a very large glandular cell. 
The proboscis of Metanemertini is divided into three cavities, which 
communicate by narrow canals, and can be evaginated only as far as the 
anterior cavity ; the posterior cavities make a secretion which is ejected 
forcibly by the musculature of the first cavity. In the adults of 
Eunemertes carcinophila reserve stilets and their pockets seem to be 
wanting. 
In Protonemertini the proboscis sheath usually extends only half the 
length of the body ; in other cases it often reaches to the anus. Its wall 
consists of a muscular sheath with a very low epithelium: in Drepano - 
phorus it has pockets alternating with the genital sacs. 
In the simplest case ( Garinina , Carinella, Pelagonemertes ) the blood- 
vascular system consists of two lateral vessels, united by commissures at 
the head and tail ends. Of general occurrence is a dorsal vessel in the 
rhynchocoelom anteriorly, below it posteriorly. Especially in Hetero- 
nemertini numerous ramifications may also occur. 
The excretory system remains undetected in Cephalothrix , Pelago- 
nemertes, and Prosadenoporus. The two canals are richly branched, lined 
with ciliated epithelium, and end in blind ampullae imbedded in the walls 
of the blood-vessels. The blood-cells are nucleated elliptical discs, 
sometimes intensely red ; the corpuscles of the rhynchocoelom are very 
large elliptical discs, with very thin margins, with a relatively small 
nucleus, and often a very distinct attraction-sphere. They may be filled 
with reddish, oily globules, but are otherwise greenish or colourless. 
The “ brain ” consists of paired dorsal and ventral ganglia, connected 
by commissures around the rhyncliodeeum or rhynchocoelom. The 
system may lie in the epithelium, between that and its basal layer, in 
the muscular layer, or still further in. In Drepanophorus, &c., the lateral 
cords from the ventral ganglia show a tendency to approach one another 
ventrally. 
The ganglion-cells always lie peripherally to the nerve-fibres. These, 
along with a very fine connective tissue, form the central substance, 
which is surrounded by an inner neurilemma. An outer neurilemma 
forms a capsule around the whole brain. Four kinds of (unipolar) 
ganglion-cells are distinguishable. 
The sense-organs are the head-grooves, the cephalic slits, the cerebral 
organs, the lateral organs, eyes, otoliths, and terminal sensory structures 
on the head. 
The reproductive elements arise either as solid balls in the paren- 
