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



this plant, l)ut do so very inaccurately, if we may be allowed to judge by the materia 

 received from him, in which it was abundant. His fig. 13 (pi. 26) does not represent 

 this species in any position, and the lateral and vertical vieAVs given by him on pi. 52. 

 figs. 13-15 are too diagrammatic. 



Long. 60-66 ju ; lat. 37-46 m; lat. isthm. 13-5-15 n ; lat. lob. pol. 30-32 ^ii; crass. 27-5-31 )u. 



Var. iNTEGRius, nov. var. (PI. XIV. figs. 23-25.) Var. lobo j)olari cum spina singula 



ntrobique infra spinam majorem, incisura infra lobnm polarem majore et latiore, 



lobis lateralibus non divisis sed subretusis, quadridenticulatis. 



Long. 52-61 ju ; lat. 32-5-41 n ; lat. isthm. 9-5-10 fx ; lat. lob. pol. 24-30 fi ; crass. 22-27 /u. 



We feel sure that this is but a variety of the above species, as they frequently 



occurred together and their surface-markings are precisely identical. E. Glaziovii, 



Boerg. (in Yidensk. Meddel. 1890 (1891), p. 36, t. 3. fig. 23), very probably comes under 



tills variety. 



55. EuASTRUM ocuLATUM, Boerg. in Vidensk. Meddel. 1890 (1891) p. 36, t. 3. fig. 24. 

 Yar. TONSUM, nov. var. (Pi. XIY. fig. 26.) Yar. minor et brevior, lateribus sine 



denticulis, apicibus truncatis, incisura apicali minus profunda, denticulis paucis intra 

 apices. 



Long, (sine spin.) 38*5 ^ ; lat. 24 ^ ; lat. isthm. 5-5 jn ; crass. 17 /". 



56. E. ELEGANS, Kuetz. Phycolog. Germ. p. 135 ; Balfs, Brit. Desm. p. 89, t. 14. 

 fig. 7 a-c. 



Yar. spiNOsrM, Ealfs, ]. c. fig. 7,/; ?, k. (PI. XIY. fig. 27.) 

 Long. 36-38-5 /j. ; lat. 22-23 /a ; lat. isthm. 6-6-5 /j. ; crass. 13-5 m- 

 A figure of a fiue and constant form of this varietv is i^iven. 



Yar. ORisATUM, West, in Journ. Boy. Micr. Soc. (1892) p. 723, pi. 9. fig. 9. 

 Long. 45 jii ; lat. 28 /j. ; lat. isthm. 10 [ju ; crass. 17*5 ;u. 



Yar. BiDENTATUM, Nacg. (? K elegans var. speciosum, Boldt, in Bihang Sv. Yet.-Akad. 



Handl. xiii. (1888) Afd. iii. n. 5, p. 9, t. 1. figs. 10, 11.) 

 Diam. zygosp. sine spin. 40-42*5 ^u, cum spin. 60-65 ^. (PI. XIY. fig. 28.) 

 Several examples of this variety with zygospores were noticed from Orono, Maine; 



they agreed very well with the figure given by Boergesen, in Bot. Tidssk. xvii. (1890) 



p. 143, t. 6. fig. 26. 



57. E. CiASTO^^ii, Eacib. in Eozpr. Akad. Krak. ser. II. ii. (1892) p. 384, t. 2. fig. 28. 

 Long. 38-5-44 /.; lat. 21-26 ^; lat. isthm. 4-5-6 ^; lat. apic. 17-19-5 ^; crass. 16-17 /<. 



(PL XIY. fig. 31.) 



This is not an unfrequcnt American species. 



58. E. SOLIBTJM, nov. sp. (PL XIY. fig. 29.) E. parvum, pauUo longius quam latius, 

 profundissime constrictum, sinu angusto lineari extremo ampliato; semicellula? 



