558 Transactions of the Society. 



cavated, ventral somewhat deeper. Sulcus very deep. Posterior 

 lobe very small. Toe short, broad, gently tapering, shouldered, 

 two-clawed. 



Length of contracted lorica 110 ^, of dorsal plate 100 /a, of toe 

 45 yL6 ; breadth of dorsal plate 115 yu,, of anterior margin 60 /i. 



The anterior angles are obtuse. The margin of the dorsal plate 

 reaches almost or quite to the anterior margin, of which only about 

 one-third belongs to the dorsal plate. The lateral sulcus is deep, 

 and the posterior extremely deep. Some examples show the little 

 frontal spines as figured by Stokes, and recalling those of M. bicornis 

 Stenroos. They do not appear to be constant, or at any rate they 

 are not always visible. The claw appears clearly double, but I 

 have never seen the parts separated. 



Mr. Harring regards M. rohusta as synonymous with M cornuta 

 MiilL, but there are two important differences — the shorter toe, and 

 the nearly straight anterior margins. M. cornuta is deeply ex- 

 cavate in front. 



Studied from examples in Mr. Eousselet's collection ; collected, 

 I believe, by Mr. Harring. 



Monostyla turho sp. n. Plate, XXII, figs, lla-lle. 



Specific Characters. — Small, ovate, truncate in front ; dorsal 

 plate much broader ; posterior lobe prominent. Toe half the 

 length of lorica, slightly expanded in the middle, obtusely 

 shouldered, clawed. 



Description. — Length of contracted lorica 70 fi, of dorsal 

 plate 55 fi, of toe 35 jjl ; breadth of dorsal plate 65 ^, of ventral 

 plate 50 /A, of anterior margin 45 /-t. 



The dorsal anterior margin is nearly straight, the external 

 angles very obtuse, and belonging to the dorsal plate, the dorsal 

 plate being here wider in front, a rare condition. The ventral 

 anterior margin projects beyond the dorsal in a rounded promin- 

 ence at each side ; in the middle a shallow excavation. 



The ventral plate has a slight constriction near the front. The 

 posterior lobe is prominent and narrow. Near the front of the 

 dorsal plate there are several transverse wrinkles, quite peculiar. 

 The anterior margins are similar to those of C. papuana (fig. 2a). 



Hahitat. — Clare Island, Co. Mayo, Ireland ; from slide in Mr. 

 Eousselet's collection ; a good many examples. 



Monostyla falcata sp. n. Plate XXII, fig. 9. 



Specific Characters. — Small, elliptical, rounded behind, truncate 

 in front. Anterior margin shallowly excavate. Toe large, broadest 

 in middle, strongly curved. Back longitudinally sulcate. 



Description. — Length of lorica 75 /jL,of toe 50 fi; breadth of lorica 

 65 /A, of anterior border 40 fi, of toe at widest part 12 fx. 



