NOTOMMATAD^E. 17 



rotatory organs to be wanting. Yet, lately I saw one on whose front a strong ciliary 

 action was conspicuous : it seemed as if the ciliate surface were on the prone side of the 

 front. The species, moreover, is furnished with protrusile auricles for augmented loco- 

 motion, like Notommata proper. I have not myself seen these, indeed ; but the fact rests 

 on ample evidence. Dr. Hudson was assured by Mr. Brayley, the Secretary of the Bristol 

 Microscopical Society, that he had seen a Taphrocampa " put out very small auricles 

 from the head, and swim with a slight vermiform movement." He had made a pen-and- 

 ink sketch of the creature in both conditions ; which sketch is in my possession, and 

 represents indubitably T. annulosa. Miss Saunders, too, a careful observer, writes me 

 under date of June 10 : " Watching your Taphrocampa annulosa a long time, I saw it 

 thrust out an ear-like lobe on each side, and swim frantically about in a most headlong 

 fashion ; but only one of three did this. The processes were not very prominent, but 

 were quite distinct." This fact affords an interesting link with the present family. 



The form of the mastax and trophi, too, though not yet quite satisfactorily denned, 

 is evidently Notommatous, and seems to resemble the pattern seen in some of the Fur- 

 cularice, and some of the Hattulida also, consisting of an incus with a long fulcrum and 

 a pair of long incurved mallei. The animal can bring the tips of the jaws to the very 

 front, and nibbles floccose matters with them. An alimentary canal, broad and straight, 

 with no accessory glands, and with no constriction, runs through the cavity to the cloaca 

 close to the forked toes. It is usually empty and colourless. At the occiput, behind the 

 mastax, and almost invariably sharing its motions in contraction and elongation, is a 

 moderate- sized mass of opaque matter, white by reflected light, and probably chalky. 

 Like a similar mass in many Notommatce, with which it is another link, it lies at the 

 bottom of a wide and deep sac. I had vainly searched for any trace of red pigment in 

 this mass which might indicate an eye. On one occasion recently, however, I was 

 examining a specimen under direct sun-light, when there suddenly flashed out from the 

 opaque mass a spark of radiance, as if from an eye-lens, though I could not discern any 

 red hue. What represents the ordinary foot and toes is peculiar. It would seem rather 

 to be a forked tail ; for I have seen, now and then, projecting beneath this, a very 

 delicate rounded lobe, which is possibly the foot, the cloaca opening between these. Or, 

 rather, it is the optical expression of the lower half of the cylindrical rectum, of which 

 the middle of the crescentic fork forms the upper part or ceiling. The intestine can be 

 traced down to this orifice beneath the fork. The fork, or, if this explanation is correct, 

 the tail, is formed of two incurved taper, chitinous, clear, sharp spines, together making 

 a semicircle ; but not separated into toes, nor articulated with the segment that carries 

 them, and so having no power of motion independent of one another, or of their 

 segment. True toes would have both. 



The animal contracts strongly and continually, like a Notommata ; but the sphere of 

 the contraction is the space occupied by the alimentary canal, the parts both before and 

 behind this viscus remaining unaffected, while the parts included contract forcibly, and 

 both ways, but chiefly from behind forward. In most of its movements it resembles 

 Ckcetonotus, crawling sluggishly about the glass, and the masses of sediment. 1 P.H.G.] 



Length. About -^^ inch. Habitat. Pools and ditches : common (P.H.G.). 



1 There are two very distinct varieties of the above, well-marked and constant ; yet with hardly 

 sufficient dissimilarity to warrant our separating them as species. The one smaller, with the articula- 

 tion strong, the lateral projections of dark tissue into each segment clearly seen, the caudal points 

 short, stout, and straight. This was the form first recognized, is the form above described, and is by 

 far the more common. The other much larger, the articulation and the interior projections both in- 

 distinct, often imperceptible ; the caudal points long, slender, crescentic, wider at their bases, and 

 making together a regular semicircle. In this variety, an excellent observation which I obtained 

 showed the mastax, mallei, and incus, almost exactly of the same familiar pattern as in Notommata 

 aiirita (PJiil. Trans. 1856, pi. xvi. figs. 16-21). 



VOL, II. 



