KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 



25. n:o 5. 75 



Long. 120-135, lat. 80—97, lar. isth. 22—30, lat. lob. pol. 50—56, crass. 

 44—50 //. Wallich gives long. 127, lat. 97 //. (Also W. Mscr. No. 193). 

 T. X, f. 28 a— d. 

 (i. (ji-unovii, Xob. (Desm. Insel Bänka p. 14, t. II, f. 22). F. lobo polari ad apicem 

 truncato, paullulum conve.No — tumöre centrali unico ornata. 



Long. 100—120, lat. 75—80, lat. isth. 25—32 u. T. X, f. 29. 

 Grunow's fig. gives long. 140, lat. 106, lat. isth, 38 ,". 

 — — forma bitumida. F. tumoribus duobus eentralibus ornata; tumöres utro- 

 bjque isthmi (paullo supra* fines sinus) transversatim positi. Specimen unicura mihi 

 visum. Ieon oraissa; in lineamentis ut in /?. 



Both these were found by me in the remnant of Dr. Wallichs gatherings; of « 

 I only saw 3 speeimens. 



4. Eu. platycerum, Reinsch (Contr. Alg. Fung. p. 85, t. All, f. 6), var. pulchiuin. Fere 

 ut in f. typica, sed semicellula' annulis granulorum eentralibus ornata 1 . 



Long. 46—52, lat, 39 — 42. lat, isth. 6—7 //. T. X, f. 44. 



Raciborski (Desm. Xov. p. 33, t, VI, f. 3) gives a. form which he styles var. 



Ttalicum of E. bellum Nordst. ; but the outline of fig. 3 a is much nearer to Rkinsch's 



plant than to Nordstedts, and 3 b is verv different. 

 i j 



5. Eu. comiuissurale, Bkéb. {Cosm. comiuissurale, in Mengh. Synops. p. 220, 1840; in 

 Ralfs' Br. Desm. p. 105, t. XVI, f. 8, 1848; Eu, commi.ssurale Wallich, Beng. Desm. 

 p. 284, 1860). 



The dimensions of this speeies vary considerably according to various authors: 

 {n typicum, semieelluUe convergentes): 



Ralfs, 1. c, long. 27.5, lat. 38 — 41.7, lat. isth. 11.7, crass. 22.3 ft. 



Wallich, 1. c., » 45.7, » 40.7, — , ,". 



Var. y Wallichii, n. v. (W. 1. c t. XIV, f. 14—16; Mscr. 191 and 209. 1855). 

 Crassum, lobo polari fere obsoleto; semieellulis divergentibus. 



Long. 26, lat. 45.7, lat, isth. 11, crass. 18 ,</. W. 1. c. 



» 26, » 46, 9, 17 ti. T. XI, f. 10 a— c. 



Raciborski (Desm. Xov. p. 33) seems to suggest that this form is more closely 

 allied to E. breviceps, Nordst., E. bellum, Nordst., and E. platycerum, Reinsch. A 

 elose eomparison of the figures shews that Wallichs vieAv is probably more correct 

 in placing this as a var, of E. {Cos.) commissurale, Bkéb. 



Var. t) capitatum, n. v. Hexiradiatum, stellatum, lobo polari protenso paullulum 

 capitato vel apjce dilatato; semicellula' divergentes. 



Long. 39, lat, 32—40, lat. isth. 7—8, crass. 15 ,». T. XI, f. Ila, b. 



Var. f> crassum, Nord.st. (Desm. Brås. p. 213, t. III, f. 19, sub Cosmario) forma? 

 Semicellula unica a me visa, Lat, 40, crass. 21 ft. T. XI, f. 27. (Lat. usquc ad 

 33 ,'/, crass. 20 ,«, Nordst. 1. c.) 



Although many authors regard this and the following forms as belonging to 

 Cosmarium, I think that the deeply incised and radiate (or distinctly lobate) forms 

 attaeh more to Euastvum than that genus; although these have the polar lobes plain, 

 crenate or serrate, and not incised, vet Wallichs remarks (p. 284 1. c.) certainly are 



