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



Cosmarmm taxichondriforme, B. Eichl. & Gutw. 

 „ Haynaldii, Schaarsclim. 



„ decachondrwn, Eoy et Biss. 



„ pseudotaxichondrum, Nordst. 



^trichondrum, Laserh. 

 ^j „ var. quadridentulum, Lagerh. 



„ notochondrum, "West. 



,, pileigerum, Lagerh. 



90. CosMARiUM CONTRACTUM, Kirclm. Algenfi. Schles. p. 147. 

 Var. MAXIMUM, nov. var. Var. diiplo-major quam forma typica. 

 Long. 8ii-88-3 p ; lat. 61-62 ^ ; lat. istbm. 17-20 (f^ ; crass. 52 /a. 



A number of examples of this variety were observed ; no intermediate forms between 

 it and the type were noticed. 



Var. PAPILLATUM, nov. var. (PI. XV. fig. 21.) Var. multo majus, sinu apertiore ad 



apicem, semicellulis papilla elongata singula ad medium lateris uniuscuj usque. 

 Long. 73 (X ; lat. sine papill. 51 /u ; long, papill. 2-3 /t ; lat. isthm. 20 /w ; crass. 44 n. 



91. C. GLOBOSUM, Bulnh. in Hedwigia, ii. (1863) p. 52, t. 9. fig. 8. 



Var. WoLLEi, nov. var. (PI. XV. fig. 17.) (C. glohosum, Wolle, Desm. U.S. p. 60, 

 pi. 49. figs. 15-17.) Var. minus profunde constrictum, sinu apertiore; semi- 

 celluli saltioribus, parte basin versus latissima ; membrana scrobiculato-punctata. 

 Zygospora depresso-globosa et glabra. 



Long. 38*5 n ; lat. 24 (x ; lat. isthm. 21 u ; long, zygosp. 34 ^ ; lat. zygosp. 28 i^i. 



92. C. PALANGULA, Breb. in Ealfs, Brit. Desm. p. 212; Babenh. PL Europ. Alg. iii. p. 174. 

 Long. 32-5 n ; lat. 13-5 ^t ; lat. isthm. 11'5 f.i. 



Genus Xanthidium, Elirenb. 



93. X. antilop(eum, Kuetz. Spec. Alg. p. 177. (Cosmarium cmtilopoeum Breb. in 



Linnaia, xiv. (1840) p. 218; X. fasciculatum, Ealfs, Brit. Desm. (ex parte) t. 20. 

 fig. 1 «, c.) 



Many forms of this were met with : var. polymazum, Nordst., w^as abundant ; var. 

 minneapoUense, Wolle (Desm. U.S. p. 94, pi. 52. fig. 16), was noticed with the median 

 subapical spine arising from both above and below the granules (fig. xylogr. 2). Another 

 form of the last variety had either one or two pairs of subapical spines and no granules. 



A peculiar form without any central granules, and which had two pairs of spines on 

 each side of the semicells arising very near each other, the upper pair being vertical, the 

 lower almost horizontal. Long. s. spin. 61 ^, c. spin. 86 /x ; lat. s. spin. 57 ^, c. spin. 92 ^ ; 

 lat. isthm. 146 ^. 



A few peculiar examples of a Xanthidium were observed, which we think must be 

 placed under X. antilopoeum, though some of them appeared to be near X cristatim 

 without the basal spines. The spines were somewhat irregular and single ones often 

 replaced the pairs. Long. s. spin. 36-5 /., c. spin. 55 ^ ; lat. s. spin. 31 /x, c. spin. 52 /.; 

 lat. isthm. 7*6 ^ ; crass. 20 ^, (PI. XVI. fig. 1.) 



