524 Hodgetts. — A New Species of Spirogyra. 
pyrenoidibus magnis instructs, anfractibus laxissimus J-iJ (-2) ; coniuga- 
tione scalariformi vel laterali velterminali ; cellulis fructiferis parte mediana 
valde tumidis ; zygosporis lentiformibus, a fronte visis orbicularibus, a latere 
late ovalibus, cellulas fructiferas non complentibus, membranae strato 
mediano verruculoso. 
Crass, cell, veget. 29-40 /x ; 
„ „ fruct. circa 90-100 /x ; 
Diam. zygosp. 50-80 (-90) j a. 
Hab. in stagno King’s Norton, Worcestershire (May 1919). 
My best thanks are due to Mr. W. B. Grove, M.A., for his kind interest 
and help during the preparation of this paper. 
DESCRIPTION OF PHOTO-MICROGRAPHS OF SPIROGYRA 
COLLI G A TA. SP. NOV., IN PLATE XXII. 
Illustrating Mr. William J. Hodgetts' s paper on a New Species of Spirogyra . ^ 
(All these figures are from untouched photographs.) 
Photo 1. The upper zygospore has been formed by semi-terminal conjugation — the empty male 
gametangium on the left is only partly shown. The lower zygospore is the result of scalariform 
conjugation. The furry appearance of the male cell is due to the pronounced fibrillar structure (seen 
better if the photograph is examined with a hand-lens) of the gelatinous sheath. Note the H-shaped 
clamp-connexion which has persisted on the end of the (lower) female gametangium. x 90. 
Photo 2. True lateral conjugation, the empty male gametangium being on the right, x 90. 
Photo 3. Semi-terminal conjugation, x 82. 
Photo 4. The zygospore on the left has been produced by terminal conjugation (the male cell is 
only partly shown on the left). The immature central zygote has been produced by an abnormal 
method compounded of the ‘terminal’ and ‘ scalariform’ methods, the female conjugation-tube being 
terminal. At the bottom right-hand corner of the photo the ends of two disjointed cells, with the 
H-shaped clamp (loosely fitting on end of upper cell) which formerly joined the cells, will be seen 
(cf. Text-fig. 4). Two examples of coiled cells are also shown, x 90. 
Photo 5. Semi-terminal conjugation. The (curved) end-cell is attached very loosely to the 
filament, and an H-shaped clamp-connexion, which has just slipped from its extremity, is shown, 
x no. 
Photo 6. Terminal conjugation and a coiled vegetative cell, x 85. 
Photo 7. Scalariform and two examples of subterminal conjugation are illustrated. Two coiled 
cells are also present, x 90. 
Photo 8. Terminal conjugation (the empty male gametangium is only partly shown). The 
H-shaped clamp has been pushed off the ends of the conjugating-cells, and is seen transfixed on the 
conjugation-tube between the two gametangia. x 90. 
