THE TARDIGRADA OF THE SCOTTISH LOCHS. 679 
called the bearers. The food passes by the gullet to the pharynx. This is a strong 
muscular bulb, through the centre of which the alimentary canal passes. The function 
of this organ is supposed to be to force the food into the stomach, which it does by a 
pumping action. In several genera there are rows of hard rods or nuts round the tube 
passing through the pharynx ; in these cases the rods seem to have the further function 
of pounding the food as it passes, thus acting as a second set of teeth. The pharynx, with 
its rows of hard rods, has some analogy with the mastax of rotifers. A short wsophagus 
leads from the pharynx to the stomach. The large cells forming the walls of the 
stomach have contents of a characteristic colour—brown, yellow, red, or blue. 
Reproduction.—So far as known, all Tardigrades are oviparous. The eggs are 
spherical, oval, or elliptical, smooth, viscous, or spiny. They are either deposited free, 
in which case they are spiny or viscous ; or they are laid several together in the skin as 
it is moulted, being then always smooth. In some genera, the larvee do not differ in 
any important degree from the adults; in others, they differ considerably, and gradually 
acquire the adult form through a series of moults. 
There is a marked uniformity of structure throughout the whole group, the main 
classification being founded on no more important characters than the texture of the 
skin, the number of claws, the form of teeth and pharynx, and the presence or absence 
of certain feelers on the head. 
EcuHIniscus. 
Generic Characters.—Skin of the back thickened and forming a number of plates or 
shields, symmetrically arranged singly or in pairs. Claws two or four, separate and 
independent. Twoeyes. Teeth and gullet long, straight; no bearers. Four short setee 
and two blunt palps near the mouth ; two longer lateral setae between the head and the 
next segment. 
Plates.—The number of plates varies, ten being most common. When this normal 
number is present they have almost invariably the same arrangement :—(1) The head 
plate or frontal plate; (2) The shoulder plate, a larger plate, crossing the back and 
extending down the sides; (3) First median plate, a small triangular plate in the 
middle of the back, the apex pointing backward; (4) First pair of plates, two equal 
plates, meeting in the middle of the back, and extending down the sides; (5) Second 
median plate, triangular, with apex pointing backward, sometimes quadrangular ; 
(6) Second par, similar to the first pair; (7) Third median, triangular, apex directed 
forward ; (8) Lumbar plate, a large plate, covering the whole posterior part of the body, 
and the fourth pair of legs, usually cut into a trefoil by two deep incisions. The middle 
portion of the trefoil I distinguish as the tail-piece. In many species described by 
RICHTERS it is quite separated from the lumbar plate, and is then called the anal plate. 
If the number of plates were constant, or if a greater or less number were due to 
subdivision or suppression, the homologous plates could be distinguished through all the 
species by their names or numbers. There are, however, some species—(L. /slandicus) 
