444 Rev. T. R. R. Stebbing on 



TrichelaspiH Forresti^ sp. n. 



General appearance. — Capital um compressed, the breadth 

 about two thirds of the length, its occludeiit margin micro- 

 scojjically crenulate ; the valves translucent, covered by 

 thin membrane, approaching or»e another at certain points, 

 but nowhere coming in contact ; the peduncle slightly longer 

 than the capitulum. 



Scuta. — The occludent segment long, narrow, widening a 

 little distally, the rounded apex approaching the tergum ; 

 the basal segment forming an angle of about seventy degrees 

 with the occludent, which it does not quite equal in length, 

 very narroWj apically pointed, the apex overlapping the fork 

 of the carina ; from the basal there arises a median segment, 

 also very narrow and pointed, a little crooked, two thirds of 

 the length of the occludent segment, from which it diverges 

 much less than it does from the basal segment. All the 

 segments are continuously calcified. The whole valve has a 

 general resemblance to the figure of the scapular apparatus of 

 a tortoise. 



Ter(]a deeply and widely bitid, so as to have a sort of 

 collar-shape, the two apices approaching the apex of the 

 occludent segment of the scutum ; the two segments or lappets 

 of the tergum are equal in length, widest at the middle. 



Carina much bowed, narrow, a little widened towards the 

 apex, which overlaps the terga without approaching them 

 very closely ; the fork at the base is variable, being in some 

 specimens much more pronounced than in others. 



Peduncle cylindrical, moderately stout, a little longer than 

 the capitulum, 



Lahrum. — The crest has a row of minute tolerably acute 

 teeth, the sides of the teeth being equal in length to their 

 bases; the central teeth are more widely separate than those 

 at the sides. 



Mandibles. — There are in all six teeth, the largest, at the 

 extremity of the convex margin, being remote from the rest ; 

 the convex border carries half a dozen pairs of setules, and 

 the distal part of the opposite border is more densely setu- 

 liferous. 



The Jivitt nia^riUa' have a group of three spines jireceding 

 the notch, which is minute ; the rest of the border, which is 

 very slightly advanced, carries five sets of smaller spines 

 mixed with setie. 



The second niaxiUa' are broadly lamellar, surrounded with 

 setaj or fiexible spines, many of which are rather elongate. 



Cirri. — The first pair are distant from the second and not 



