Notes on the Family Cathypnidtv. By J. Murray. 557 



posterior lobe. The latter is large, and separated by a deep cou- 

 striction from the trunk. There is a " hood " as in M. galeata, etc. 

 Hahitat. — In Mr. Eousselet's collection. Probably one of Mr. 

 Bryce's original specimens. 



Gathypna sulcata Gosse {^3). Plate XXII, fig. 5. 



Description. — Small, shortly oval, truncate in front. Dorsal 

 plate much broader than ventral, even at extreme front, longi- 

 tudinally sulcate. Toes short, tapering, acute. 



Length of contracted lorica 80 /i, of dorsal plate 70 fi, of toe 

 32 //, ; breadth of dorsal plate 70 yLt, of ventral plate 45 yLt, of frontal 

 margin 50 yLt. 



This is a very doubtful identification, made on the strength of 

 the longitudinal sulci and narrow ventral plate. Gosse shows 

 minute frontal spines and toes, not tapering. His representations 

 of toes in this family are, however, unreliable, as, for instance, in 

 the figure of M. lunaris. 



Hahitat. — Top of Eonas Hill, Shetland. 



Monostyla constricta sp. n. Plate XXII, fig. 10. 



Specific Characters. — Fairly large, roundish ; dorsal plate broader 

 in middle than ventral, much incurved in front, truncate behind. 

 Ventral plate much constricted anteriorly ; anterior margin deeply 

 excavate between sharp angles, trefoliate, the sulci deep ; posterior 

 lobe scarcely projecting beyond dorsal plate; toe long, tapering, 

 obtusely shouldered and clawed. 



Description. — Length of contracted lorica 125//,, of dorsal 

 plate 110 fjb, of toe 80 p, ; breadth of dorsal plate 105 p, of ventral 

 plate 95 />6, of anterior margin 40 p. 



The dorsal plate is ovate, truncate behind. The margin is 

 incurved in front to an unusual degree, reaching far towards the 

 middle line. It cannot be traced quite to the frontal margin, but 

 the points separating the three curves of the trefoliate excavation 

 undoubtedly mark the limits of the dorsal plate. The sulci are 

 very deep, especially the posterior one. The toe is somewhat narrow. 



The species is related to M. lunaris, but is distinguished by 

 the much constricted front, less prominent posterior lobe, and 

 longer toe. Two long-toed species discovered by Mr. Harring 

 have wider, less excavate anterior margins, and still longer toes. 



Hahitat. — Daatzig, from specimen in Mr. Eousselet's collection. 



Monostyla rohusta Stokes (.f/). Plate XXIII, figs. 21a-2lb. 



Descrip)tion. — Large, round. Dorsal plate slightly larger in 

 middle, very narrow in front. Anterior margins shallowly ex- 



