670 Beady and Norman — Monoc/raph of the 3Iarine and Freslmater Ostraeoda 



Genus 7. Paramekodon,* n. g. 



Shell in ? oval, excessively tumid, breadth sub-equal to height, antennal 

 sinus a mere concavity, in front of which the rostrate j^rocess is projected 

 directly forward ; surface of valves in type species punctate and hispid. 

 Antennules (PI. lix., fig. 3), six-jointed, without sensory organ on fourth joint, 

 with terminal setae sub-equal, two of them of remarkable character, flattened, 

 membranous (fig. 3 «), and closely waved in wrinkles ; antennae without any 

 appendicular branch, in its place a large-ringed, plumose seta (fig. 4) ; mandible 

 (fig. 5) with masticating process divided, but only at the extremity ; no peculiar 

 spines on the second joint, but the laminar appendage at its extremity well 

 developed, limb ending in a single unguis of great length ; first maxilla (fig. 6) 

 short ; second maxilla devoid of anterior lobes, teeth enormously developed, the 

 upper (fig. 8) consisting of a great sub-oblong plate, with spiny processes on the 

 margin, and terminating at tlie anterior extremity in a large fang, vibratory 

 lamina well developed (fig. 7), external palp consisting of a single lobe ; 

 penultimate appendages without vibratory lamina (fig.) 9. 



Paraniekodon inflatus, n. sp. 

 (PI. LIS., figs. 1-10.) 



Shell of female regularly and broadly ovate, beyond which the rostrate 

 process projects forward, and at the infero-posteal corner there is a slight lip-like 

 protrusion of the valves; the antennal sinus is small, caused by the junction of 

 the perfectly erect obtusely rounded rostral process with the natural and 

 continued inward sweep of the ventral margin ; ventral and dorsal margins 

 very bold and evenly arched, the latter with a slight sign of angularity 

 at its junction with the somewhat obliquely truncated upper portion of the 

 posterior margin, the lower portion of which margin is sliglitly protruded, as 

 already mentioned. Form excessively tumid, greatest height central, equal to 

 five-sevenths of the length, and the breadth sub-equal to the height. Seen from 

 above, the outline of form, excejDt the extremities, is almost identical with the 

 lateral view ; greatest breadth central, sides very boldly and evenly arched, 

 posterior extremity very broad ; anterior, with the rostral portion much more 

 compressed. Valves rather thin, surface very finely punctate, and sparingly hirsute. 



Antennules (fig. 3) six-jointed, first joint longer than the combined length of 

 two following joints ; second and fourth joints sub-equal on the inner margin, the 

 former the longer on the outer ; third and fifth joints sub-equal, and each about half 



* TrapafxiQKrj^, oblong ; oSaiv, a tooth . 



