1. C.192.c.1, 4(226) Reference (shelfmark): C.192.c.1, 4(226) Title: Polysiphonia obscura. Photographer: Atkins, Anna Scope & Content: Genre: Scientific Photography Cyanotype negative photogram of two algae specimens, on paper watermarked, 'J Whatman Turkey Mill 1851,' and with British Museum yellow datestamp of 11 Oct 1851 on reverse. Collection Area: Printed Collections Languages: Not applicable Date Range: 1851 Extent: 1 item