KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 25. N:0 5. 121 



I dedicate this distinct little species to a good niicro-observer, and my valued 

 friend, Dr. John Roy, of Aberdeen. 



72. S. iiieditum, n. sp. S. raedioere; fere tam longum quam latum (incl. proe.); semi- 

 celluhe fusiformes, dorso convexa?, e basi regulariter expansa*; angulis 3 in processus 

 rectos singulos productis, angulos versus processubus brevioribus 3 dispositis (1 dorsali 

 et 2 ventralibus); processus omnes apice furcati; membrana lavi; sinu aperto, brevi, 

 rotundato. A vertice visum triangulare, lateribus convexis, versus apices attenuatis. 



Long. 36, lat. 28 (s. proc); long. et lat. 48 (c. proc); lat. isth. 11; long. proc. 

 ang. 10 — 11, long. proc. caet. 6 — 7 ju. T. XV, f". 27. 



This is probably the same as the form included by Delponte under his species 

 »SV. iutricatiun (Desm. sub. alp. t. XI, f. 16, 21, co2t. excl.), in which certainlv 3 di- 

 verse forms are described. 



73. S. Japonicuin (R. & B.) nob. (St. Hantzscliii var. ft Japonieum Roy and Bisset, Jap. 

 Desm. p. 240, t. 261), f. 5). S. mediocre, quarta vel quinta parte longius quam latum 

 (proc. incl.); semicellulis a fronte visis perfecte globosis, dorso radiis 5-7 sub-longis 

 rectis fere erectis apice bitidis instructis; ventre radiis 8 — 10 longioribus rectis fere 

 horizontalibus apice bitidis munitis; semicellulis glabris non sub-lobatis ut in St. intri- 

 cato Delp., nec cuneato-fusiformibus ut in St. Hantzschio Keinsch; radiis lavibus non 

 margine serratis vel dentatis; sinu aperto, rotundato, in visu basali circulo granulorum 

 suturam circum ambiente. A vertice visum 8 — 10-radiatum, angulis interne rotundatis. 



Long. 37—40, lat. 18—21 (s. proc); long. 46—50, lat. 33—40 (c. rad.), lat. 

 isth. 10—12, long. rad. 10—13 fi. T. XVI, f. 24. 



The number of rays in this form våries cöfisiderably ; taking the vertical ones 

 first and the horizontal ones in successi(^n, I hafe noted forms thus, 5 — 8 one speci- 

 men, figured; 5 — 9, figured; 6 — 9 R. et B. 1. c; 6 — 10; 5 — 10. It appears to be 

 nearly related to St- foptaeamtåutn Nohdst. (Desm. Brås. p. 230, t. IV, f. 46), but 

 differs much therefrom in bcing smaller and with considerably shorter arms, which 

 are not so widely expanded at the furcate a})ices. 



74. St. Bissetii, n. sp. S. minus, fere tam longum quam latum; semicellulis cuneatis, 

 dorso late et ventre paullo rotundatis, triangulatis; quoque aiigulo j;rocessubus brevil>us 

 rectis lavibus apice furcatis 7 (3 et 3 utroqne latere verticalibus, et 1 centrali) ar- 

 mato; membrana glabra; sinu aperto, rotundato. A vertice visum triangulare, lateribus 

 paullo incurvatis, processubus radiantibus divergentibus. 



Long. 26, lat. 18 (s. proc); long. 30, lat. 32 (c proc); lat. isth. 8, long. proc 

 5-7 /u. T. XVI, f. 26. 



To my kindly correspondeut J. P. Bisset, of Banchory, (coadjutor of Mr. Roy 

 in micro-botany,) I dedicate this distinct form. 



75. S. rusticum, n. sp. S. minus, quinta parte latius quam longum; semicellulis irregu- 

 lariter cuneatis, dorso convexis, ventre inflatis, hevibus; angulis 3, in processus paullo 

 convergentes, minute aculeatos, apice 3—4 dentatos, produetis; quorpie angulo proces- 

 subus brevibus 2 erectis bitidis, cum aculeo brevi crasso unico inter verrueas 2, or- 

 nato; parte centrali frondis lavi; sinu brevi, acuto. A vertice visum triangulare, late- 

 ribus in centrali parte fere rectis apice acutis. 



K. Sv. Vet. Akud. Iluiull. Baud. 25. N:o 5. 16 



