86 THE EOTIFEEA. 



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

 clmeil to identify with S. redunca of Ehr. ; but 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 .5. macracantha bears to 

 ventralis. I have seen several examples ; one from the Lake at The Grove, Stanmore, 

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



Length, ^ inch ; horizontal ■width, jly inch ; depth, wJ,3 inch. Habitat. "\Yool- 

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



S. SULCATA, Gosse, sp. uov. 



(n. XXII. fig. 7.) 



[SP. CH. Occipital spines tn-o, sUgldly lyrocurvcd ; pectoral ttco, straight, acute ; 

 Ivaabai single, short, with a icidencd base; alvines longer, straight; dorsal cleft re;-// 

 u-ide, with 02itcu>vcd edges. 



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

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

 occipital incurved. In the rear, the ahdne 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, cm-ving outward to the occipital spines (figs. 7, 7b), 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 deluieated at fig. 7b. 



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 fi-om 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 sufiiciently 

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



Length. Of lorica, without toes, yj-^y inch ; transverse width, ^j,- inch. Habitat. 

 ■Woolston (P. H.G.) : rare. 



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

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

 figures (PI. xxii. fig. 3). He has added no note to this form ; but his delineations were 

 made from specimens procured from a secluded pool near Sandlmrst 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 behmd, where its edges termmate in two very slightly prominent lumbar 

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

 as sulcata looks toward Diplols, yet both appear to be true Salpinx. — P.H.G.] 



Genus DirLOlS, Gosse, gen. nov. 



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

 equal 2>lttes, nnited by clastic membrane; the dorsal plate arched, ridged, and split 

 doivn the middle; the ventral y?ai ; toes straight, furcate ; eye single, cervical. 



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

 Bpecie:;.) 



