1888-89.] Mr John Rattray on the Genus Coscinodiscus. 471 
Habited. — Oran deposit (Ehrenberg) ; Oamaru deposit (Grove and 
Sturt); Mejillones guano (Deby! Hardman! Firth!); Peruvian 
guano (Cieve ! Johnson !) ; Chincha Island guano (Arnott !) ; Arica 
and Saldanha Bay guanos (Ehrenberg); off Bermuda, 1075 fathoms 
(Kae !) : Loch Fyne (Greville !) ; Lamlash (Gregory !) Biarritz, Bay 
of Biscay (Brebisson !) ; Black Sea (W. Smith) ; Java (Cieve) ; 
Amboina shell scrapings (Kinker !) ; Ascidia, Roundstone Bay, 
county Galway (O’Meara !) ; S. America (Moller !) ; * Lough Hym, 
county Cork (Grove!); Kirkwall, Orkney (Grove!); Edible sea- 
weeds, India (Macrae!); Locality? (Barnett ?f Weissflog !) ; 
Valparaiso (Schmidt); Villefranche, Trinidad (Cieve and Moller !); 
Campeachy Bay (Grove !) ; Monterey Stone (Cieve !) ; Balearic 
Islands, Pabillan di Pico guano, Bolivian guano (Cieve !) ; Port 
William, Falkland Islands (Rabenhorst and Schwarz !). 
C. bisculptus, sp. n. C. labyrinthus, Roper, var.? Sch., Atl., 
pi. lix. fig. 14. — Diam. *035 mm. Surface somewhat convex. 
Central space and rosette absent. Markings large hexagonal or 
pentagonal, unequal areolae, 2 to 2J in *01 mm., somewhat smallest 
towards the centre ; within these more minute, faint, angular 
areolae — the larger in obscure radial, but more evident oblique 
substraight decussating lines, the smaller without order. Border 
sharply defined, about \ of radius broad; striae coarse, 3 in *01 mm. 
Habitat. — Peruvian guano (Schmidt). 
C. labyrinthus. Roper, Quart. Jour. Micr. Soc., 1858, p. 21, 
pi. iii. figs. 2 a, 2 b. — Diam. *0625 to *0875 mm. Central space 
absent. Markings hexagonal towards the centre 4, decreasing 
gradually to the border to 6 in *01 mm., punctate, forming 
straight or slightly curved oblique decussating rows and distinct 
secondary subequal hexagonal, areolae from ”0025 to *0085 mm. 
broad; minute apiculi sometimes present at the border. Border 
indistinct ; striae 7 to 8 in ”01 mm. — Ralfs in Pritcli. Inf., p. 831 ; 
Cieve and Moll., Hiat., No. 276 (excl. C. labyrinthus, Roper, var.? 
Sch., Atl., pi. lix. fig. 4). 
The smaller hexagonal markings recall those of C. excentricus , 
Ehrb., and of C. sol., Wallich. At the centre a faint stellette is 
* In the collection of Julien Deby. 
t In the collection of Dr Griffin. 
