PALMELLACE^E. 21 



Dictyosphaerium renif oxme . Buln. Hedwigia n. 22. 



Families aggregated in an irregular form ; cells reniform, 

 nearly twice as broad as long. 



SIZE. Cells -008--009 mm. (Rabh), -006--01 X '01--02 mm. 

 (Kirch.). 



Rabh. Alg. iii. 47. Rabh. Exs. 789. Archer in Micro. 

 Jonrn., 1868, viii. p. 65. Kirch. Alg. Schl. p. 106. 



In pools. Near Snowdon, N. Wales. 



" This plant possesses larger families than D. Ehrenbergianum, which 

 are irregularly shaped, seemingly owing to the development of the 

 delicate supporting fibre not going on in the same regular manner as in 

 the preceding species, and the cells themselves are much larger and 

 reniform." Archer. 



Plate IX. fig. 2. a, b, plants magnified 400 diam. ; c, portions show- 

 ing filament. 



Dictyosphaerium constrictum, Archer (M icr. Journ., 1866, p. 128) 

 having been afterwards found to produce zygospores (see " Micro. 

 Journ.," 1875, p. 415), has been transferred to the Desmidece 

 in company with Cosmocladium, to which genus it seems to be 

 allied. 



Cosmocladium Saxonicum, DeBary, is sometimes placed by 

 authors (as in Rabenhorst's Algas) in this family. But, as 

 DeBary demonstrated in "Flora" (No. 21,1865), the cells 

 proceed in the same manner as in Cosmarium, and therefore its 

 proper place is with the Conjugates^ as one of the Desmidece. 

 It has been found in North Wales. 



GENUS 15. HORMOSPORA. Breb. (1840.) 

 Thallus tubular, gelatinous, swimming free. Cells oblong, 

 or oval, green, arranged in simple longitudinal series (families), 

 either remote from each other, or more or less united at the 

 poles. Tegument thick, confluent, contained within the broad 

 gelatinous tube, which is either simple or branched. 



* Tubes simple. 

 Hoxmospora mutabilis. Breb. Mem. FaL 1840. 



Tubes intricate, more or less broad, or parallel and coalescing ; 

 cells twice as long as broad, broadly rounded at each end ; 

 tegument very thin. 



SIZE. Cells 011--017 mm., tube diam. -043 mm. (Rabh.). 



Rabh. Alg. iii. 48. Breb. in Ann. des Sci. Nat., 1844, t. i. 

 f. 2. Kirch. Alg. Schl. p. 108. 



In boggy pools. Ireland. 



Plate X. ficj. 1. a. portion of filament X 300 : b, same breaking up 

 X300. 





