88 THE ROTIFERA. 
be a sharp medial line, but that it is split throughout, and so forms a narrow furrow 
with low walls. Though the fisswre can be distinctly traced to the occipital edge of the 
lorica, I am not quite sure that the ridge, or wall, begins to rise above the dorsum-level 
quite so early ; perhaps not till the middle of the length, and then gradually. The two 
strong sharp points at the hinder end of the dorsum, so conspicuous in many aspects of 
the living animal, are but the optical expression of the ends of the dorsal ridges seen 
vertically. The ventral plate is sensibly less in outline than the dorsal: it is ovate with 
the pectoral edge truncate ; flat, thin, and glassy; at each extremity it becomes delicately 
membranous. The foot consists of three distinct joints, long, and regularly diminish- 
ing; they are habitually extruded between the plates, perhaps in a sinus of the ventral ; 
but I am not sure of this. The toes are moderately long, slender, blade-shaped, being 
(very slightly) dilated beyond the middle, and then rather abruptly pointed. No sets are 
visible. The condition of the dorsal cleft is not invariable. Sometimes it is seen to 
extend not more than half-way up from the tip: or even to be closed nearly to the 
points, expanding there rather suddenly. Possibly the lorica is elastic, and subject to 
the animal’s will; for I have certainly seen the fissure wide throughout. The hyaline 
transparency of the whole, while it enhances the beauty of the creature, increases the 
difficulty of discerning all particulars of its structure, even those that are external ; 
especially as, from the incessant movements and changes of axis in swimming, it is almost 
impossible to focus any one part in any one position. The front consists of a number of 
low prominences, each rising to an obtuse cone, and each crowned with a row of vibrating 
cilia. The mastax, an oblate sphere, presents nothing noteworthy; the brain descends sac- 
like behind it, with a round deep-red eye near the middle of its internal side, distinctly 
crowned with a refracting lens. The stomach and intestine, not separable, occupy a 
large space in the body-cavity, usually filled with contents of an uniform rich deep-brown 
hue. ‘This greatly adds to the animal’s beauty, as it constantly roves up and down the 
narrow cells made by the crossing filamentous leaves of Myriophyllwm in the live-box. 
In general form and appearance this species very closely resembles the larger Hu- 
chlanes, which all its manners and actions perfectly represent, and do not in the least 
remind one of a Salpina. It is a fine addition to our Rotiferous fauna. Since it appears 
new, I honour it with the name of Miss Davies, of Woolston, Hants: a lady who has 
long made the Rotifera her special study, and to whose courtesy I am indebted for my 
first knowledge of the species. 
Specimens have come under my observation, not only from the extreme south of 
England, but, on repeated occasions, from Scotland. It is, however, rare.—P.H.G.] 
Length. Extended, ; inch. Habitat. Woolston; Dundee (P.H.G.). 

Family XIV. EUCHLANIDA. 
Lorica of two dissimilar plates, one dorsal, one ventral, united so as to form two 
confluent cavities, of which the upper is much the larger ; foot jointed, furcate. 
Genus EUCHLANIS, Ehrenberg. 
GEN. CH. Dorsal plate with the medial portion arched ; ventral plate nearly flat, 
usually with a flange on either side; eye single, just above the mastax. 
There are no more beautiful or perplexing Rotifera than those contained in the genus 
Euchlanis. Their large size and brilliantly transparent lorice render them most attract- 
ive objects for dark-field illumination ; and it is by this method of exhibiting them that 
the true structure of their loricze can be best determined. The animal must have room 
enough to swim at its ease, and there must be a few bits of alge for it to creep on. 
Then, as it turns while swimming, or as it works its way over and round the weeds, the 
creature will display all the beauties of its glassy armour; which, invisible at one 
moment, wall flash out at another in broad plates and unsuspected surfaces. 
