the Oreensand compared with those of existing Species. 139 



Laminarian zone at Budleigh-Salterton that it is impossible 

 to examine microscopically a portion of Sponge, Echinoderra 

 (visceral contents) or Compomid Ascidi an without seeing 

 several of them. They, but for their delicate natm-e, would 

 It may therefore be assumed, have been as numerous in the 

 Haldon deposit as they are in tlie deep sea and in the Chalk 

 which they might have contributed to form just as much as, if 

 not more than, the other minute organisms found in it : for the 

 coccohth IS but a Melobesian cell {Melohesia umceUularL mihi), 

 which, like the arborescent M. calcarea on the south coast of 

 i)evon, may form beds of many miles in extent, entire as they 

 die or tragraental as they pass out in a comminuted stati 

 trom the alimentary cavities of the lower animals (e. g As- 

 cidta amchnoidea,Yovhes), which feed upon their protoplasmic 

 contents most voraciously. Hence, too, perhaps their pelleted 

 grouping m the form of coccospheres, if these are not their 

 sporangia. 



Besides sponge-spicules in this deposit, I have seen minute 

 bivalve shells and a few minute Foraminifera, but no remains 

 which I could m any way identify with the calcareous spicules 

 o± i^chmodermata, Alcyonida3, Gorgonida3, or Ascidic^. 



EXPLANATION OF THE PLATES. 



N.B All the figures in these plates, excepting 7, 8, and 9 are taken 

 from the fossilized remains of sponges in the Uppe'r GreeJsand of ?Ialdon 

 Hill, near Exeter, and of Black Do^^n^, near Cullompton, respectiyelv 

 and « are draw on the scale of l-24th to l-1800th of an' incirin S 

 that their relative sizes maybe seen and their measurements respec- 

 tively computed by compass and rule. let-pec 



The fractured ends of the shafts or branches are represented by a point 

 or ittle circle wi hm a larger one, the former being intended for the cen- 



whrpL^sfiy^^' ^'^ ''''-' ^^^ ^^^ "^^"-^--- «^ *^« «p^-^-^ 



re^^^tli^HnS^fte^^b^a^Se^^^- "^^ ^^^^^^^ '^ 



Plate VH. 

 Figs. 1 & 2. Disks of Dactifhcah/cites Vicuryi. 

 Fif/s. .3-5. Disks of Dactyl'ucah/cites pohjdiscus. 



Fi^ 6. Disk oimctylucalycitespcar^^^^ lateral view, showing the shaft. 

 I'tg. 7. Disk of Dacttjlocalyx polyihscus, Bk., after Schmidt, showino- the 

 r- o T^??^ ®. branching of the axial canal of the shaft (a). 

 itg.S. Disk oiDactylocalyx polydiscus, m. {Discodermia polycliscus, 



Bocage), after Bocage, showing the ternate division of the axial 



canal of the shaft (a). 

 Fig. 9. The same, lateral view, showing the shaft. 

 Figs. 10 & 11.^ Rectangular branching of silicified fibre like that of ^«- 



Fig. 12 Canalled silicified fibre like that of Farren occa, Bk 

 i'tys. 13-18 Knots or branching centres of silicified fibre, like that of 

 JJactylocaiyx . 



10* 



