168 MR. W. WEST OT* THE FRESHWATER 



Upper Lake of Killarney ; near Lough Brin ; Adrigole ; Car 

 rantuohill. 



2. Arthrodesmus Incus, Hass. (Balfs, Brit. 

 tab. 20. fig. 4o-rf, non e-h). (PI. XXIV. fig. 11.) 



(sine spin.) 17 a ; diam. zygosp. ( 



27 



P 



I. Moher Lough ; near Leenane ; Derryclare ; Shannacloon- 

 tippen and Letereen Loughs ; Lakes, Clifden to Roundstone 

 and near Recess ; Kylemore ; Ballynahinch ; Eoundstone ; near 

 Westport; near Oughterard; Lakes E. of Lough Bofin. 

 II. Lough Gruitane; Carrantuohill ; Adrigole; near Lough 

 Briti ; Lower Lake of Killarney (cum zygosp.) ; Cromagloun ; 

 Muckross ; Sugar Loaf Mt. 

 , Forma apicibus constanter convexis. 



Long, sine spin. 23-25^; lat. sine spin. 25-26 p; lat. cum 

 spin, 45-50 p; long. spin. 13-17 /x ; lat. isthm. 10-15 /z. 



I. Ballynahinch. — II. Grlengarriff. 





tVar. intermedius, Wittr. (Anteck. Skand. Desm. p. 15, 



%. 6.) 

 I. Athry Lough. 



tt3. A. Ralysii, nov. sp. 



[A. Incus, Hass., Balfs, Brit. Desm. tab. 20. fig. 4 e-h, 

 nee a-d.~\ 



A. mediocre ; celluhe diametro l^plo longius (sine aculeis), 

 modice constrictum, sinu lato et aperto ; semicellulse latissime 

 campanulas, angulis inferioribus gibbosis, angulis superioribus 

 spinis longis validis subinflexis adornatis, apicibus subconcavis ; 

 a verticaB visse anguste ellipticse, spina longa valida ad polum 

 utrumque ; membrana glabra. 



L Eoundstone; Derryclare Lough. — II. Castletown; Adri- 

 gole ; near Lough Brin. 



This differs from A. Incus, Hass., in its somewhat larger 

 , its subquadrate semicells, its subconcaye ends, its generally 

 more open sinus, and its incurved spines. 



t4. A. triangularis, Lagerh. {Bidrag till Amcrik. Desm. 

 Fl. p. 244, tab. 27. fig. 22.) Forma. (PL XXIV. fig- I 9 -) 

 I. Ballynahinch. 



size 



