12G THE EOTIFERA. 



animal's form ; as it is hard to see how its extravagantly long spines can be of much 

 service to it. They evidently forbid its approach to the confervas and floating rubbish 

 that are the favourite haunts of its class, under penalty of being probably anchored for 

 life to the same spot ; and they can scarcely serve as floats, for the animal is a heavy 

 swimmer, as if overburdened with these great projections, and is usually found four or 

 five feet below the surface. Neither can they be very serviceable as weapons of defence, 

 for even the fry of a gudgeon would soon learn to snap it sidewise. At any rate it is a 

 most interesting form, and though rare and impatient of captivity it is easily managed in 

 the compressorium, as it can be firmly yet lightly held by its long curved spines without 

 injury. The lorica is triangular in outline, the dorsal surface convex both lengthwise 

 and across, the ventral slightly concave and rather more sharply curved as it approaches 

 the hind end. Six spines spring from the anterior edge of the lorica. Two are lateral, 

 and are continuations of thickened ridges running part way down the edges where the 

 dorsal and ventral surfaces meet. They are equal in size, taper to a point, and curve 

 first outward and then upwards and inwards. Then, on either side of the median dorsal 

 line is a strikingly unmatched pair. One, the largest of all the six, is stout at the base, 

 tapering to a point, and curved first downwards and then upwards, with a graceful 

 sweep. The other is an abortive looking spine, of uniform thickness, about one-fifth 

 of the length of its partner. In the gap between these two lies the dorsal antenna ; and, 

 as this antenna is exactly on the median line, it follows that the longest spine is not in the 

 middle of the lorica (as it has been hitherto drawn '), but slightly on one side of it. There 

 is yet another pair of spines, of equal length, considerably shorter than the lateral spines, 

 and lying one on each side between the dorsal and lateral pairs. The hind end of the 

 lorica flows off into yet another tapering spine curving downward and then upward, like 

 the longest ; and, with it and the body, presenting on a side view an elegant sigmoid 

 curve. At the top of the ventral surface the lorica has a square flap, which can move, 

 as on a hinge, to permit the head to come out, and which closes over it, when it is with- 

 drawn. There is also a slit, like a trap-door at the hind end of the ventral surface, 

 through which the cloaca is emptied. All the front spines are rough, but the hind spine 

 is smooth. The corona has a thick dorsal wall crowned with ciliated eminences, and 

 surrounding a deep cavity leading to the buccal orifice. This cavity is thrown open on 

 the ventral surface by a scalloped V-shaped slit ; and is guarded at each side on the top 

 by two teat-shaped protuberances armed with stout vibrating styles. All the edge of 

 the corona is ciliated, and so are the edges of the ventral slit, at the bottom of which lies 

 the buccal orifice. The mastax with its sub-malleate trophi is close to the buccal orifice. 

 There is a distinct oesophagus bearing two stalked glands below the mastax, and a cluster 

 of rather larger glands just above the stomach. The gastric glands, stomach and intes- 

 tine require no notice. A contractile vesicle lies just below the latter, close to the 

 cloaca ; the lateral canals and vibratile tags are conspicuous. The muscular system is 

 like that of B. riibens (i. p. 8) ; and it is curious to see how, owing to the flexibility of 

 the lorica, the longitudinal muscles can draw together all the frontal spines. As these 

 are really continuations of stout chitinous ridges in the lorica itself, the approaching 

 spines, with the flexible lorica folding up between them, look exactly like a closing 

 umbrella. My specimens died before I had seen the nervous ganglion ; but there is a 

 dorsal antenna, protruding between the longest and the abortive spine when the head is 

 expanded, and pulled in when the head is withdrawn. The adult had a single red eye, 

 at the lowest part of the occiput, near the dorsal surface. Mr. Levick says that many 

 of the first specimens that he found had two eyes ; and that he thinks these animals 

 were young ones. It would be very curious should it prove to be the case that two eyes 

 in the young approach with age, and coalesce in the adult ; especially as Bracliioni 



1 Dr. Kollicott, Mr. Levick, and Dr. Imhoff, all place the largest frontal spine exactly on the median 

 line of the lorica, and half-way between two small spines ; I am satisfied that this is a mistake. Dr. 

 Imhoffs figure shows four small frontal spines besides the three long ones : this also is wrong ; there 

 are only three, the abortive spine and a pair. 



