248 MESSES. W. WEST AND G. S. WEST ON 



Many examples of this species were seen, and they were quite constant and perfectly 



symmetrical (1). 



C. impressum, Elfv., is a fairly common species in the United States of America. 



74. CosMARiUM Uegnellii, Wille, in Bihang Sv. Vet.-Akad. Handl. viii. (1884) n. 18, 

 p. IG, t. 1. %. 34. (PL XV. fig. 20.) 



Long. 14-5-l7"5 ^ ; lat. 15-5-19 n ; lat. isthm. 5-5*5 fi. 



This species was rather alumdant, and was fairly typical, though the subapical notches 

 were not so deep as figured by Wille. 



75. C. suBLATEREUNDATUM, Wcst & G. S. AYcst, in Trans. Linn. Soc. ser. IL, Bot. v. (1895) 



p. 60, pi. 6. fig. 1. 

 Long. 42-46 fx ; lat. 38-5-41 ^ ; lat. isthm. 12-13*5 n. 



The specimens were a little larger than the original ones, and had one more undulation 

 on each side of the semicells. 



76. C. CYATHIFORME, uov. sp. (PI. XV. fig. 9.) C submediocrc, tam longum quam 

 latum, profunde constrictum, sinu angusto-lineari extremo ampliato ; semicellulse 

 subtrapeziformes, angulis inferioribus superioribusque leviter rotundatis, lateribus 

 divergentibus et subrectis, apicibus valde convexis, granulis circ. 11 intra apicem 

 (juxta marginem) et angulos superiores, infra eos serie granulorum majorum 5, et 

 granulis multo minoribus circ. 5 subter iis ; a verticc visse ellipticse polls truncatis, 

 granulis magnis 5 utrobique et granulis 9 intra marginem unumquemque instructs^; 

 a latere visie cyatbiformes apicibus truncatis, granulis tribus ad margines superiores 

 et granulis (circ. 6) intra marginem superiorem utrobique ; pyrenoidibus binis. 



Long. 35 /ii ; lat. 34 ^ ; lat. isthm. 7"5 ^u ; crass. 21 n. 



This approaches both C. hexagonum, Nordst. in Vidensk. Meddel. 1869 (1870) p. 208, 

 t. 3. fig. 18), and C. insigne, Schmidle, in Ber. naturf. Ges. Preib. i. Br. vii. (1893) 

 p. 100, et in Plora, Ixxviii. (1894) p. 56, but differs from them in the form of its cells 

 and the arrangement of its granules. 



77. C. Eloiseanum, WoUe, Desm. U.S. p. 85, pi. 19. figs. 1, 2. (PI. XV. fig. 22.) 

 Wolle has given a figure of this species which is quite inaccurate, and as his description 



is also incorrect we give both figure and amended description. In his Preshw. Alg- 



U.S. p. 33, he says that the figure he had drawn w^as an old form and had too many 



teeth ; he should have said three times too many. 



C. submagnum, l^-l-|-plo longius quam latins, profunde constrictum, sinu angusto, 

 extrorsum ampliato ; semicellulae late elliptical, margine serie dentium magnorum 

 acuminatorum 25-28 [23-25 (Wolle, Alg. U.S.)], in centro inxirassat^ et scrobiculis 

 magnis ornatoe ; a verticc visse ellipticaR polis subtruncatis, ad medium utrobique 

 tumore scrobiculato, seriebus duabus subrectis dentium de polo ad polum ornatae; 

 membrana luteola punctata. 

 Long, sme dent. 98 fx ; cum dent. Ill fx ; lat. sine dent. 62 /n, cum dent. 76 fi ; l^t- 



isthm. 25 ^ ; crass. 46 ^. 



The teeth are rather suddenly attenuated, and the two series in vertical view are not 



