KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 25. N:0 5. 51 



This little form is perhaps nearest to Archeks own species C. erosum (sp. ined.), 

 non Delponte No. 55, q. v. 



20. C. trmodiferum, n. sp. Cos. minus; paullo longius quam latum; depresso-ovale; sinu 

 lineari, aequale, extrorsum ampliato; semieelluke cuneato-truncatas, angulis inferioribus 

 rotundatae, dorso truncata'. Membrana pro maxima parte laevis, sed sub-apicibus tribus 

 nodulis (in triangulo positis), et apud margines utroque latere serie granulorum (circ. 

 5 — 6) ad basin diminuenda, ornata; marginibus minute crenulatis. 



Long. 17, lat. 15, lat. isth. 5 ,«. T. VII, f. 37. 

 Bengal; Northern India. 



21. G. etenoideum, n. sp. C. minus, ovale-depressum; paullo longius quam latum; semi- 

 cellulae cuneato-truncatae, angulis inferioribus rotundatae, apieibus paullo exsertai; mar- 

 gine (lateris 3, apicis 5) crenata?; sub utraque crena granula posita; merabrana in aliis 

 laevi; sinu lineari, extrorsum ampliato; apieibus truncato-crenatis. A vertice ovale, 

 paullo ventricosum. 



Long. 22—25, lat. 20, lat. isth. 6—7 ,u. T. VII, f. 39, VIII, f. 59. 



My friend Dr. Nordstedt asks »Are there not 2 granules at some of the crense, 

 but not at all?» To this I may reply that the two figures are from distinet specimens, 

 and are figured as I saw them. The species appears to be intermediate between ('. 

 suberenatum Hantzsch (in Rabh. Alg. 1213; Fl. Kur. Alg. III, p. 164) and C. sub- 

 costatum Nordst. in X. et W. (Desm. et (Edog. p. 37, t. XII, f. 13); it is also near 

 to C. substriatum Nordst. (W. et N. Alg. No. 977, 1889) but is without the extra 

 granules at base, and the central nodule. 'Cos. sp.' Wittr. Gott. Öl. Sötv., t. IV, f. 

 15, is probably a smooth form of this species. In outline it much resembles it. 



22. C. centrosphinctum, n. sp. C. sub-mediocre, circ. l^/^-plo longius quam latum; isthmo 

 constricto, angusto; sinu amplo, interne rotundato; semicellulEe fere globos». Membrana 

 glabra, sed apud apices ordine granulorum minutorum (granulis centralibus maximis) 

 instrueta; membrana achroa sed saepe rubido-luteola. C. moniliformi (Turp.) Ralfs 

 proximum. 



Long. 38, lat, 24, lat. isth. 6 u. T. VIII, i. 1. 



23. C. circulare, Reinsch (Spec. Gen. Alg. p. 113, t. 22 C. i, f. 1—4, 1867). 



Long. 56, lat. 61, lat. isth. 26 ,«. 

 Bengal; Central India; verv common. 



24. C. corruptum, n. sp. C. mediocre, polymorphum; paullo longius quam latum; semi- 

 cellula 1 ovatae, plus minus altae; angulis inferioribus late rotundata 3 , dorso convexa 1 ; 

 isthmo modice constricta,'; sinu sublineari, extrorsum ampliato; membrana punctata, vel 

 minute granulosa, achroa vel pallide fusco-luteola. A vertice visum compresso-ovale, 

 apieibus paullo attenuatis, rotundatis; a latere fere biglobulatum. Zygospora globosa, 

 dense aculeis longis obsessa. 



Long. 48, lat. 44, lat, isth. 17—20 ^, er. 22 fi. T. VIII, f. 2. 



50, » 44, » 18 »21—22 a. T. VIII, f. 2 b. 



C. circtilari Reinsch (1. c.) et C. scenedesmo Delp. (Des. Sub-Alp. p. 101, t. VII, 

 f. 28 — 34) intermedium. 



