554 Transactions of the Society. 



Habitat. — Unknown. Several slides of the species are in Mr. 

 Eousselet's collection, without the localities noted.* 



Cathypna hrachydactyla. Stenroos {46). Plate XXIII, fig. 15. 



Description. — Fairly large, somewhat rhomboid. Dorsal plate 

 narrower than ventral. Anterior border straight, bounded by 

 small spines. Posterior lobe very prominent. Toes short, broad, 

 tapering, acute. 



Length of contracted lorica 135 /x, of dorsal plate 105 /i, of toe 

 30 /a; breadth of dorsal plate 90 /x, of ventral plate 100 /x, of 

 anterior border 55 /x. 



Drawn from specimen in Mr. Eousselet's collection, found in 

 material collected by Mr. Lucks, near Danzig. 



Cathyfna ligona Dunlop {12). Plate XXIII, fig. 16. 



Description.— Oi moderate size. Dorsal plate much narrower 

 than ventral, truncate both ends. Sulci shallow. Posterior lobe a 

 broad hyaline process, with almost straight posterior border. Toes 

 short. 



Length of lorica llO /x, of dorsal plate 90 fx, of toe 25 /x ; 

 breadth of dorsal plate 78 fi, of ventral plate 90 /x, of anterior 

 border 68 /x, of posterior process 60 /x. 



Habitat. — Fort Augustus, Scotland ; drawn from specimen in 

 Mr. Eousselet's collection. (Eeceived from Mr. Dunlop, Gfeenock.) 

 As the animal had died extended I cannot show the contracted 

 form of the anterior margin. 



Cathyjpna spinifera Western {51), Plate XXI II, fig. 17. 



Description. — Of moderate size, elongate. Dorsal plate much 

 narrower than ventral, faceted, truncate both ends. Anterior 

 margins nearly straight. Posterior lobe small, narrow, truncate. 

 Toes very short, tapering, acute. Lateral sulcus moderately deep. 



Length of lorica 120 /x, of dorsal plate 110 /x, of toe 15 /x ; 

 breadth of dorsal plate 55 /x, of ventral plate 70 /x, of anterior 

 border 50 /x. 



Two recurved prickles near posterior end of membrane. The 

 dorsal facets are few and large, quite unlike those of other species. 



The figure is drawn from a specimen in Mr. Eousselet's collec- 

 tion. The species has been well described, and illustrated by good 

 figures by Mr. Dixon-Nuttall. My figure is here reproduced in 

 order to show all the species to one uniform scale. 



* Since writing this paper I have f?een abundance of specimens in Mr. Earring's 

 collection in Washington, so that it is likely that Mr. Eousselet's examples emanated 

 from this source. 



