GOMPHONEMA. 273 



var. dichotomum. (G. dichotomum IF. St//. ; H.V.H. Atl., pi. 24, 

 f. 19, 20, 21*), plate 7, fig. 310. 



Less naviculoid, upper apex of valve more obtuse and gently 

 constricted; stride finer, 12 or 13 in 1 c.d.m. Length, 3'o to 4^5 c.d.m. 



Freshwater. England (Comber, Norman). Scotland (W. Sm.). Ireland (W. Sm.l. 

 Sweden. Finland (Cleve). 



var. auritum. (G. auritum A. Braun; H.V.H. Atl., pi. 24,1. 

 15* ; in Type No. 212), plate 7, fig. 311. 



Verv narrowly lanceolate and less rhomboidal ; in the living state 

 furnished with two mucous hyaline horns (see H.V.H. Atl., pi. 24, f. 



Fresh water. Frahan (Delogne). Scotland. Finland, Norway, &c, (Cleve). 



G. micropilS Klltz. (Baa, pi. 8, f. 12; H.V.H. Atl., pi. 25, f. 4 

 and 5; pi. 24, f. 46*; Type No. 219, a form passing into parvulum), 

 plate 7, fig. 312. 



Valve lanceolate, feebly gomphonemoid, with lower moiety regularly 

 attenuate as far as the apex, more or less subacute ; the upper moiety a little 

 inflated, with apex very slightly rostrate, capitate. Striae approximate to raphe, 

 feebly radiant, 10 in 1 c.d.m. Length, 2-5 to 3 c.d.m. 



Fresh water. Rather rare ? Aid. Lig. (DeWild.). Glasgow, Scotland. Fiance (Brebisson. I 

 bb. The /too apices of valve almost equally obtuse. 



G. intricatum Kutz. (Baa, p. 87, pi. 9, f. 4; h.v.h. Atl., pi. 24, 



f. 28, 29 : Type No. 214 [a variety]), plate 7. fig. 313. 



Valve narrow, almost linear, length about 6 to 8 times the breadth, a little 

 inflated at the median portion. Raphe surrounded by a considerable hyaline 

 zone ; nodules distant from the apices. Striae feebly radiant, 8 to 10 in 1 c.d.m. 

 Length, about 4 to 6 c.d.m. 



Fresh water. Ard. Lieg. ( De Wild.!. England (Comber, Norman). Ireland (O'Meara). 



var. vibrio. (G. vibrio Ehr., Verb., p. 128, pi. 2, i., fig. 40 ; H.V.H. 

 Atl., pi. 24, f. 26 and 27*; Type No. 216), plate 29, fig. 812. 



Exactly resembles the previous form, from which it only differs in its 

 size being larger, which attains 9 c.d.m., and by the stauroneiform hyaline 

 area being much more distinct. 



Quiet fresh water. England (Normani, Ireland (O'Meara). France, Prussia, and pro- 

 bably others. 



G. angUStatum KlltZ. (Baa, p. 83, pi. 8, f. 4 ; G. commune Rab. ; 

 H.V.H. Atl., pi. 24, f. 48, 49, 50*; Type No. 2.5), plate 7, fig. 314. 



T 



