116 THE EOTIFEEA. 



It is somewhat slow of motion. The medial line of the venter is a salient angle ; and 

 this has a curious effect as the creature revolves. P.H.G.] 



Length. Of lorica, 7 ^ inch. Habitat. Pond at Lower Clapton (P.H.G.). 



P. SULCATA, Hudson. 

 (PL XXVII. fig. 2.) 

 PompJiolyx siilcata . . . Hudson, /. Roy. Micr. Soc. 1885, p. 613, pi. xii. figs. 7, 8. 



SP. CH. Lorica entire, divided into four convex lobes, by four longitudinal 

 furrows. 



The lorica of this species is very unlike that of Mr. Gosse's P. complanata. In the 

 latter the dorsal and ventral surfaces are so compressed that they are slightly concave, 

 while in the former both these surfaces are sharply convex, and so are the connecting 

 lateral surfaces. A transverse section, consequently, consists of four segments of circles, 

 as shown in fig. 26. It is easy to obtain this view, as well as a good sight of the corona 

 with its two wheels and red eyes, for the animal is fond of swimming upright close to 

 the cover-glass, or of exploring the bottom of the live-box, head downwards. I had little 

 opportunity for studying the creature, but I noticed that the lorica had an aperture in 

 its lower, pointed, and somewhat curved extremity. 



I am indebted to Mr. Bolton for this pretty little Rotiferon, which he discovered in 

 company with Conockilus dossuarius in the summer of 1884. 



[A curious habit which this genus has in common with Bracliionus is that of carrying 

 the eggs, after they are successively discharged, until the young burst the shell. These 

 are nearly circular (absolutely so as often presented to the eye), very large in propor- 

 tion to the animal, each connected by a highly elastic thread to the hindmost part of 

 the lorica, between its two terminal points. This thread can be lengthened or shortened 

 at the will of the animal, and this in a surprising manner ; for by very careful observa- 

 tion I perceived that, in elongating, the slender elastic thread was actually projected, the 

 egg of course being inert, and nothing pulling or even touching jt. And to a surprising 

 extent ; for I have seen the thread to equal in length the longer diameter of the egg. 



The front edge of the lorica rises to a rounded projection dorsally, and two of less 

 elevation laterally ; these latter appear to be separated by a shallow sinus pectorally. 

 The mastax is small, the trophi formed on the pattern seen in Pterodina, an incus with 

 small fulcrum and quadrantiform rami, and with obsolescent mallei. I have seen re- 

 traction of the anterior parts to such an extent that the foot of the incus was very 

 nearly at the bottom of the visceral cavity. P.H.G.] 



Length, ^ inch. Habitat. Near Birmingham (T.B.) : rare. 



Family XVIII. BRACHIONID^. 



[Lorica box-like, open at each end, generally armed with anterior and posterior 

 spines ; foot long, excessively flexible, wholly retractile, wrinkled, ending in two toes. 



Genus BEACHIONUS, Ehrenberg. 



GEN. CH. Lorica without elevated ridges, gibbous both dorsally and ventrally ; 

 foot very flexible, uniformly ivrinkled, without articulation, toes very small. Lacustrine 

 and marine. 



This genus contains Rotifera mostly of large size and of showy appearance, being 

 inclosed in glassy shells of regular outline, adorned with symmetrical projections, and 

 always presenting a broad surface to observation. They have been favourites with 

 observers from the dawn of microscopy ; and they are still. Fortunately most of the 

 species are common and easily accessible. The form of the foot is peculiar ; it is a long 



