RATTULID^E. 35 



ment, it is probable that the adult animal remains for a long time in one place. Some- 

 times it seeks 1 its nourishment vegetable detritus and decomposed particles of Nebalia's 

 e gg g by bending its body nearly at a right-angle and feeling about with its head, 

 stretching its swan-like neck in all directions, and every moment retracting it completely 

 into the trunk. 1 



MASTIGOCEECA COBNUTA, Eyferth (PI. XXXIII. fig. 21). 



Monocerca cornuta , Eyferth (46). 



SP. CH. Body a long cone, with a long very low dorsal ridge, continuous with the 

 frontal spine ; front beset with five projecting spines ; toe nearly as long as the lorica ; 

 no sub-styles. 



There is one spine continuing the dorsal ridge or groin beyond the edge of the lorica ; 

 this is the longest of the five. Opposite to it, from the ventral edge, project a pair of 

 about half the size ; and there is also on each side another short spine, dividing the 

 space between the dorsal and ventral spines. Herr Eyferth adds that the long toe is 

 slightly bent downwards, so that the dorsal spine, dorsal ridge, and toe together form a 

 curve : a curve, however, which his figure hardly shows. 



Length. Including the toe, ^ inch. 



MASTIGOCEBCA IEBNIS, Gosse (ill), (PI. XXXI. fig. 26). 



[SP. CH. Body long-oval ; a long dorsal ridge throughout, rising abruptly with an 

 oblique edge in front ; toe not so long as lorica ; sub-styles two, unequal, the chief one 

 about one-third as long as the toe, remote from it at the base. 



This species has much resemblance to M.. scipio ; but the regular form of the lorica 

 and that of its ridge, and the origination of the toe and of the main sub-style, on oppos- 

 ite sides of the foot-bulb, so as to be remote from each other, seem sufficient peculi- 

 arities to warrant its distinctness. 



Several examples have occurred in Utricularia vulgaris, sent me by Mr. W. E. Hood 

 from a lough in the heart of Ireland. Most of these were dead, mere empty loricae, 

 affording excellent opportunities for precise observation and delineation ; others were 

 alive and active. I subsequently found it in water from Carmock Chase, sent by Mr. 

 Bolton. The distinctive characters noted above were conspicuous in all : as also in some 

 vigorous examples from Perthshire. In these the extremities of the jaws were occasion- 

 ally protruded. I detected, moreover, on the front, three tubercles (one central and two 

 lateral), which seemed fleshy, extensile, and retractile. 



Length (entire), ^ inch. Habitat. Lacustrine. P.H.G.] 



MASTIGOCEBCA BICBISTATA, Gosse (169), (PI. XXXI. fig. 27*. 



[SP. CH. Two equal sub-parallel carinae, running nearly the whole length of the 

 dorsum. 



Discovered near Dundee by Mr. Hood, who sent me from time to time many examples- 

 It has a general likeness to M. carinata, but is much larger. The double* carina con- 

 firms the conjecture that the asymmetry of that and other species is due to unequal 

 development. 



The carinae are thick at their base, and sharp at their edge, so that the furrow is 

 sharp at the bottom, and has sloping sides. 



Length, ^ inch, of which the toe is nearly half. Habitat. Dundee (J.H.). P.H.G.] 



MONOCEKCA VALGA, Elirenberg (42), is probably a male Rotiferon. 



1 The whole of the above account of the Seisonidca has been taken from a translation of the 

 Mitthcilungen aus der Zoologischen Station zu Neapel, Bd. vii. pp. 234-263, published in the Annals 

 and Magazine of Natural History, No. yii. July 1888. 



r> 2 



