HA RD WICKE' S SCIENCE- G OSSIP. 



59 



Between the two rows are a pair of sharp spines 

 occurring close together, side by side, upon the 

 mid-dorsal line. The anus 'opens just behind the 

 more posterior of the two rows, whose spines are 

 always conspicuous from apparently terminating the 

 body as the animal lies back upon its retracted foot. 

 All the dorsal spines upon the trunk project upwards 

 in a formidable manner as the creature crawls, but 

 incline backwards when the animal is retracted. 



Upon the foot itself at least two rows of small 

 spinous points exist, crossing the dorsal surface 

 transversely, as "well as probably a few scattered 

 spines ; but as this appendage is usually quite hidden 

 within the trunk, except when the animal is crawling, 

 the exact number and position of the foot-spines is 

 not easily arrived at, nor is this at all important. 



The longest bristles upon the body equal in length 

 the dorsal antenna ; they are swollen at their bases so 

 as to remind one of a nettle-hair seated upon its 

 basal bulb. 1 have met with specimens in which the 

 spinous appendages were not provided with the long 

 terminal setae usual in other individuals, but this is 

 evidently a mere unimportant variation, the result 

 of accident, for I have seen, on another specimen, a 

 spine evidently (from its unsymmetrical condition to 

 its fellow) broken off above the swollen basal portion, 

 and another bent sharply at right angles at the same 

 point. 



The only Macrotrachela hitherto known as possess- 

 ing spinous processes is M. aculeata (Milne), but in it 

 these are all wide scale-like processes resembling 

 those of Philodina aculeata, and very different from 

 the long bristles of the present species ; curiously 

 enough, Mr. Bryce has found a third spine-bearing 

 form, distinct from either of the preceding, which 

 he has described at a recent meeting of the Quekett 

 Club, under the name of M. sfinosa. 



The general shape of the body when the coronal 

 lobes are expanded, bears a resemblance to that of 

 M. quadricornifera, but with, of course, the addition 

 of the spines ; the coronal wheels also resemble that 

 species, except that they are narrower. In M. mul- 

 iupinosa, the moderately wide corona expands 

 scarcely wider than the neck, and consists of two 

 distinct lobes, separated by a noticeably deep square 

 sinus, in width equal to half that of each "wheel." 



The neck is but little more than one-third the 

 greatest width of the trunk, and the fully-expanded 

 coronal wheels less than one-half the latter. 



The frontal column is thick, cylindrical, moderately 

 long (about same length as the dorsal antenna), and 

 terminated by strongly developed cilia beneath a 

 minute hood. 



The dorsal antenna is rather more than three- 

 quarters neck-width in length, stout, two-jointed, and 

 with three terminal tufts of parallel-projecting setse : 

 it can be slightly nodded, in a similar manner to 

 what is seen, very much more evidently, in Rotifer 

 macroceros. 



Eye-spots are entirely wanting. The mastax 

 exhibits two prominent thick teeth crossing each 

 ramus, and numerous fine striae. 



The food within the stomach is not moulded into 

 pellets, as is constantly done in some allied species ; a 

 host of small spherical globules do occur within the 

 body, and are liable to be mistaken for food-pellets, 

 especially as they are frequently seen moving about 

 en masse. These globules represent, I think, the 

 highly sacculated, thick, glandular wall of the 

 stomach, beneath which the minutely granular food 

 may be seen turning over and over locally within the 

 central lumen, by the action of the lining cilia. The 

 intestine wall is thin and non-glandular. 



A large opaque brown ovum within one individual 

 bore witness to the oviparous mode of reproduction. 

 The foot-spurs, seen dorsally, appear as very small, 

 blunt cones, as figured, with an interspace between : 

 in side view, they are seen to be very slightly 

 decuived. The toes, apparently three in number, 

 are thick, fleshy, and truncate, with distinct ducts 

 running through them. 



All the specimens of this form that I have seen have 

 been extremely sluggish creatures, lying in the retracted 

 condition, with both the fore-parts and the foot with- 

 drawn within the trunk, in the manner customary 

 with Bdelloids, often for many hours at a time. For 

 this reason, it is considerably difficult to hit upon an 

 individual nicely expanded and feeding, with rotating 

 wheels, so as to secure a sketch of the animal in that 

 state ; especially as specimens are few and far 

 between. The body is much flattened from dorsum 

 to venter and broad in its central part, both in 

 retraction and when expanded. The animal varies 

 in colour from a scarcely perceptible yellow tinge, 

 almost colourless, to a decided brownish yellow, in 

 different specimens, probably according to age. 



When fully outstretched, the trunk is seen to pass 

 backwards gradually into the foot, which is very 

 short. 



The individuals of this species have a characteristic 

 mode, when feeding, of sitting up upon their retracted 

 foot, supported by the five small spines upon the rear 

 of the trunk, and with their bodies held upwards in 

 the water at an angle, and wheels rotating. 



The length of the animal, as retracted, varies from 

 r.' m inch to T J 3 inch in different specimens ; when 

 sitting back upon the foot, rotating, about ^ inch. 



Sf. Chars: — Body broad and flattened, yellowish 

 or brownish, furnished with numerous long bristles 

 and shorter spines arranged along definite lines, the 

 longest bristles with slightly bulbous bases. Corona 

 moderately wide, scarcely wider than the neck, of 

 two distinct lobes, with a deep square dorsal gap 

 between. Dorsal antenna rather more than three- 

 quarters neck-width, with three terminal tufts of 

 parallel setEe. Rami with two prominent teeth. 

 Food in stomach not in pellets. Foot-spurs minute, 

 blunt cones. 



