680 Brady and Norman — Monograph of the Marine and Freshwater Ostracoda 



Genus 2. Nkmatohamma,* n. g. 



Shell of male obliquely subquadrate, hinder extremity very widely and very 

 obliquely truncated, rostrate process not at all projected downwards, being 

 abruptly truncated inf eriorly ; antennal sinus widely gaping ; surface of valves 

 rugose. Antennules bearing a nodiform appendage at the hinder extremity of 

 antepenultimate joint, the appendage covered with a dense cluster of very long 

 filaments, and also furnished with a long annulated seta. Antennae with secondary 

 appendage small, but formed for gi-asping. Mandible without any masticating 

 lobe or peculiar spines at the base, third joint of palp very short, last joint 

 carrying a single unguis. Copulatory appendages having terminal hooked 

 processes. 



Female unknown. 



The curious dense cluster of very long filaments attached to a short clavate 

 process on the antennules, and the structure of the mandibular foot, are the chief 

 characters which separate the type of this genus from all other Myodocopa. 



Nematohamma obliqua, n. sp. 



(Plate Lii., figs. 1, 2; Plate liii., figs. 12—15.) 



Shell of 3 subquadrate, abruptly and very obliquely truncated behind ; 

 greatest height subcentral, equal to three-fifths of the length ; ventral margin 

 with only slight arcuation ; dorsal margin highly convex centrally, but only 

 gently arcuated towards the extremities; hinder margua abruptly widely and 

 obliquely truncated, forming distinct angles at its junction with ventral and dorsal 

 margins. The anterior extremity is bluntly rounded, without any sign of a 

 beak, the lower side rising at right-angles fi'om the bottom of the antennal 

 sinus, which is shallow and completely open above, with its lower edge gently 

 convex. Surface of valves very uneven, punctated, and furnished with many 

 elevations and hollows ; a strongly developed rib crosses the anterior extremity ; 

 the central portion of the shell is depressed, and surrounded by rib-like elevations, 

 enclosing a subquadrangular space, which is wider behind than in front. The 

 lower much elevated riblet which encloses this space is waved, being incurved 

 in front, then boldly convex before it sweeps upwards at some distance from the 

 hinder extremity to meet at a sharp and nodulated angle the riblet which bounds 

 the enclosed space above ; that riblet is arcuate, and runs at some little distance 



* i'^//a, a thread ; a'///ia, a knot, /. e. a knot of filament in allusion to the appendage of the antennules. 



