86 THE ROTIFERA. 



This large and handsome species, one of the finest of the Salpina, I was at first in- 

 clined to identify with S. redunca of Ehr. ; hut it is more than double the size of that 

 species, and the great development of its alvine spines sufficiently distinguishes it. It 

 may be regarded as bearing the same relation to redunca as S. macracantha bears to 

 vcntralis. I have seen several exatnples ; one from the Lake at The Grove, Stanmore, 

 the residence of my esteemed relative, Mrs. George Brightwen. P.H.G.] 



Length, V inch ; horizontal width, T | ? inch ; depth, ^J 3 inch. Habitat. Wool- 

 ston ; Stanmore (P.H.G.) : rare. 



S. SULCATA, Gosse, sp. nov. 

 (PI. XXII. fig. 7.) 



[SP. CH. Occipital spines tiro, slightly procurved ; pectoral two, straight, acute ; 

 lumbar single, short, with a widened base; alvines longer, straight; dorsal cleft very 

 wide, with outcurved edges. 



The lorica is of the usual outline, but somewhat wide, both in the vertical and 

 lateral aspects. Of the anterior spines the pectoral are the shorter and straight, the 

 occipital incurved. In the rear, the alvine pair the longer, and recurved ; the lumbar 

 short, straight, acute, with an abruptly widened cuneate base. From this lumbar 

 point two dorsal ridges run up, curving outward to the occipital spines (figs. 7, Ib), in- 

 closing a shallow depression, which appears covered with only membranous integument. 

 The lorica, on the ventral surface, is quite continuous and evenly rounded. I had some 

 protracted and satisfactory sights of the creature in various positions, particularly from 

 a point directly in the rear, and at different angles, by which I distinctly saw the dorsal 

 furrow. One of these views is carefully delineated at fig. Ib. 



I know this form only from a single specimen just dead (but with the soft parts not 

 yet decayed), which occurred, Sept 14, 1885, in water from Woolston Pond, sent me 

 just a month before. It seems to be undescribed, yet well-marked by its broad dorsal 

 furrow, widening forward. It has no relationship 'with Ehrenberg's S. bicarinata, from 

 which, however (to judge by his figures, for of diagnosis he gives none), it is sufficiently 

 distinct. It is a small but interesting form. P.H.G.] 



Length. Of lorica, without toes, T ^ 7 inch ; transverse width, ^{ 7 inch. Habitat. 

 Woolston (P.H.G.) : rare. 



[I am indebted for my knowledge of a very distinct species, S. mutica, to Dr. Collins's 

 Note-book of pencilled sketches, minute but carefully executed. I have enlarged his 

 figures (PI. xxii. fig. 8). He has added no note to this form ; but his delineations were 

 made from specimens procured from a secluded pool near Sandhurst Military College, in 

 December 1866. He identifies the species with S. mutica of Herr Perty. 



From these it appears that the lorica does not vary much from the normal form (as 

 in S. brevispina, for instance) ; save that the front is straightly truncate, without any 

 spines, that the dorsal fissure is narrow and shallow throughout, and that it slightly 

 widens behind, where its edges terminate in two very slightly prominent lumbar 

 points : alvines seem wholly wanting. This species looks toward the genus Diplax, 

 as sulcata looks toward Diplo'is, yet both appear to be true Salpince. P.H.G.] 



Genus DIPLOIS, Gosse, gen. nov. 



[GEN. CH. Lorica, more or less depressed, ovate in outline ; formed of two sub- 

 equal plates, united by elastic membrane ; the dorsal plate arched, ridged, and split 

 down the middle ; the ventral flat ; toes straight, furcate ; eye single, cervical. 



shaped expansion, into the upper obtuse point of the bladder. (See the description of the preceding 

 species.) 



