SALPINADJE. 87 



Of the two noble species for which this genus is constituted, the general form and 

 aspect suggest their location in the next family, while the technical characters fix them 

 here. At the first glance at their elegant forms, like ample oval plates of the clearest 

 glass, evidently broader than deep, we hesitate not instantly to pronounce them normal 

 Euchlanes ; but a moment's observation reveals a fissure through the back, so charac- 

 teristic of the Salpinadce. The affinity between Diplols propatula and Salpina sulcata 

 is very close. 



The internal organization, so far as observed, agrees with that of Euchlanis. 



It is possible that the E. bicarinata of Herr Perty and the E. Weissii of Dr. Leydig 

 may belong to this genus ; but I have seen no diagnosis, or figure, of either. P.H.G.] 



D. PROPATULA, Gosse, sp. nov. 

 (PL XXIV. fig. 2.) 



[SP. CH. Dorsal cleft wide before, closed behind; ventral plate considerably less in 

 outline, furnished with three spines behind ; toes very long, of uniform thickness. 



This species is broadly ovate, sometimes nearly circular, in outline, the dorsal plate 

 strongly arched, and medially ridged ; the ridge cleft so widely that the lorica is oblit- 

 erated at its front in a vertical view, forming an acute point at each side. Each side of 

 the fissure, from the lateral point, approaches the other in a graceful curve, till, at the 

 hind-back, they unite at an acute angle. The posterior margin of the plate extends 

 beyond this, forming the uninterrupted segment of a circle. The ventral plate is of 

 similar outline, but very much smaller, and quite flat. It ends behind in three acute 

 spines, of which the laterals diverge and the middle one projects from the general level. 

 The foot, of strongly marked articulations, is protruded between the plates ; the toes, of 

 great length and tenuity, are straight, of uniform thickness throughout, with blunt 

 points. No setae have been detected on the foot-joints. The internal organization pre- 

 sents nothing distinctive, so far as it has been observed. 1 



The interspace between the lorica-plates is considerable ; and this, together with the 

 great width of the dorsal cleft, produces a curious effect, as the animal twists about, 

 making the triple character of the lorica, with its points and angles, very apparent. 



This distinct and imposing form has but recently come under my personal observa- 

 tion. But it is figured by Dr. F. Collins in his Note-book, from specimens obtained 

 twenty years ago near Sandhurst Mil. Coll. Figs. 2 and 2a are carefully copied from 

 his pencil sketches. 2 On two separate occasions I have found the species, at each time 

 in water sent from the original pool, which thus is its only recognised habitat. Its 

 motions are elegant and lively, and its appearance most attractive. P.H.G.] 



Length. Fully extended, about ^ inch. Habitat. Pool at Sandhurst, Berks (Dr. 

 Collins ; P.H.G.) : rare. 



D. DAVIESI^, Gosse, sp. nov. 

 (PI. XXIV. fig. 3.) 



[SP. CH. Dorsal cleft narroio, parallel-sided, open througlwut; ventral plate nearly 

 equal, with no posterior sirines ; toes blade-shaped. , 



This species occurred in water dipped from Miller's Pond, Woolston, The lorica is 

 decidedly triquetrous, the dorsal plate rising with sides slightly bulging, to what would 



1 It will be observed, however, that while in my own figure (2a) the gastric glands are of the ordinary 

 form, Dr. C. has represented a pair of large pyriform sacs, each containing a vacuole, with long and 

 slender ducts which lead from (or into) the oesophagus. These suggest the remarkable structure found 

 in Pterodina, to which I refer the reader. 



2 The toes are here represented as out-curved ; whereas, in the living examples I have seen, these 

 organs were quite straight. Dr. Collins is a very accurate observer, and the length and curvature of 

 the toes ("slightly curved") are distinctly mentioned in his MS. notes. In his transverse section, 

 moreover, the lorica-plates are much closer together than I have seen them. Possibly, in both these 

 particulars, there is some individual variation. 



