364 Transactions of the Society. 



lorica, which yet was very membranous. When eagerly chewing, not 

 only the mallei worked, but a pair of additional horn-like pieces, well in 

 front of the mastax. A very small and indistinct red eye is near the 

 occipital extremity of the brain. (Fig. 5.) 



6. Dapidia stroma. Outline ovate, dorsum high, rounded : carapace 

 much exceeding the viscera in width, and turned-in beneath with straight 

 margins ; viscera protected exclusively by membrane. Length 1/65 in. 

 Lacustrine. 



Dr. Hudson (Eotifera, ii. 89) has alluded to my opinion that certain 

 species oiEuchlanis are generically separable by the character of wanting 

 a ventral plate ; the lateral edges of the carapace, which turn in beneath, 

 being united only by flexible and expansible skin. My esteemed col- 

 league difiiers from me; and, on a matter so exceedingly delicate and 

 difficult to determine, I may be in the wrong. But I am not convinced ; 

 and I hope it is not inconsistent with modesty or friendship to record 

 my own judgment. The species, I think, is undescribed, whatever its 

 generic place. 



The carapace is shaped (if I may use so homely a comparison) like a 

 boat turned bottom up, her bows cut off sharp, her gunwale curved-in, 

 and no keel. Suppose the cavity of the boat to be loaded, half-way up, 

 with goods [the viscera], and a tarpaulin [the common skin] to be spread 

 over all, but higher in the middle than at the sides ; the head-mass, of 

 living fleshy organs, to be thrust out at the truncate and open bow, 

 filling it ; and the foot and toes to represent the rudder ; — a fair idea 

 will be conceived of this fine form. There are no foot-setae. 



It may easily be supposed to possess a ventral plate. But what 

 looks like one, on a (nearly) lateral view, is the edge of the farther 

 incurved side of the carapace ; when viewed from behind, there is no 

 lateral infold or sinus running longitudinally. I have seen numerous 

 examples. (Fig- 6.) 



7. Colurus leptus. Lorica, in dorsal aspect, long oval ; in lateral 

 aspect, abruptly excavate behind ; dorsal hind points, acute : ventral 

 cleft close, insensibly expanding to a long pyriform foot-orifice: toe a 

 slender style, apparently undivided ; foot and toe about half as long as 

 lorica : one large eye in occiput. Length, extended, 1/300 in. Lacus- 

 trine and marine. 



A marked character, very easily recognizable, is the hind excavation 

 of the lorica, as if a slice had been cut clean out. Examples with this 

 peculiarity are quite common, both from weedy fresh waters, and from 

 rock-pools on our northern and southern coasts. And I can trace no 

 difierence between them, save that the marine examples may be a trifle 

 stouter in outline. The toe is a slender produced point, I will not say 

 indivisible, but not, in my experience, divided. Several oil-globules are 

 usually present in the dorsal part of the visceral cavity. (Fig. 7.) 



8. Biglena (?) pachida. Body thick, sub-cylindric, very variable in 

 outline : skin leathery, thrown into strong folds : eye wanting : toes 

 two, furcate, long, slender, acute, decurved. Length 1/87 in. Marine. 



Several examples of this curious thickset form, — more remarkable 

 than attractive,— occurred to me last summer, in sea-water from various 

 rock-pools in Torbay. It is uncouth, heavy and sluggish, apparently 



