88 THE EOTIFERA. 



be a sharp medial line, but tbat it is split throughout, and so forms a narrow furrow 

 with low walls. Though the fissiire 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 liN-ing 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 dorf?al : it is ovate with 

 the pectoral edge truncate ; fiat, 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 setse 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, hicreases 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 

 ciha. 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 Myriophyllum in the live-box. 



In general form and appearance this species very closely resembles the larger Eu- 

 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 Eotiferous 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, ^V i"ch. Habitat. Woolston; Dundee (P. H.G.). 



Family XIV. EUCHLANID^. 



Lorica of two dissimilar i^latas, one dorsal, one ventral, united so as to form tu-o 

 confluent cavities, of wliich the upper is much the larger ; toot jointed, furcate. 



Genus EUCHLANIS, Ehrenhcrg. 



GEN. CH. Dorsal plate luith the medial portion arched ; ventral plate nearly flat, 

 visually ivith a flange on either side ; eye single, just above the mastax. 



There are no more beautiful or perplexing Rotifora than those contamed in the genus 

 Euchlanis. Their large size and brilliantly transparent loricm 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 loriciE can be best determined. The animal must have room 

 enough to swim at its ease, and there must be a few bits of algffi 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, will Hash out at another in broad plates and unsuspected surfaces. 



