150 BRITISH PALAOZOIC SPONGES. 
30. GzoprtEs antiquus, Hinde. Plate V, figs. 3, 3 a—3 d. 
1883. Guropta?P antigua, Hinde. Cat. Foss. Sponges, p. 208, pl. xxxviii, figs. 5, 
5a—de. 
Detached bifid and trifid zone-spicules, with elongated, cylindrical, or sub- 
cylindrical shafts, and simple, short, obtusely-pointed head-rays, projecting 
obliquely forwards at angles between 45° and 52°. The shafts in all the spicules 
are incomplete, the longest fragment measures 2 mm.; they vary from ‘15 to *25 
mm. in thickness. The spicular head-rays are about ‘35 mm. in length. Detached 
acerate spicules occur in the same beds with the trifid spicules, and also in other 
beds in which no trifid forms have as yet been found. These acerates are fusiform, 
straight, or slightly curved, smooth, and pointed. Provisionally they may be 
regarded as belonging to the same species as the trifid forms. They vary from 
2 mm. to 3°9 mm. in length and from ‘1 to ‘22 mm. in thickness. 
Distribution.—Yoredale series: Harrogate, Richmond, Arkendale, Yorkshire ; 
Halkin, Trelogan, Flintshire. Carboniferous Limestone: Clitheroe, Lancashire. 
Lower Limestone series ; Low Baidland (J. Smith); Law Quarry, Dalry (J. Bennie). 
Upper Limestone series, Glencart, Dalry (J. R. 8. Hunter, J. Smith). 
31. Gropites perormis, Hinde, sp. nov. Plate V, figs. 4, 4a—4g. 
This species includes very robust bifid and trifid zone-spicules, their shafts are 
straight or slightly curved, thickest near the summits, where they are slightly 
compressed ; below the summits the shafts are circular in transverse sections. In 
several specimens the head of the shaft extends slightly beyond the point from 
whence the head-rays are given off (Plate V, 4/), and there is usually a small 
central depression at the top of it. The spicular rays are relatively short, stout, 
conical, and obtusely pointed; they project obliquely forwards at angles varying 
between 45° and 70°. In the bifid spicules the head of the shaft is usually com- 
pressed and the rays are opposite to each other. ‘I'he rays in the same spicule are 
apparently inequal in length; they range from °7 to 1-4 mm. in length by *4 mm. 
in thickness near their bases. The shafts in all the specimens yet discovered are 
broken and incomplete; they vary in thickness from ‘6 to 1:05 mm. 
Accompanying the bifid and trifid spicules are unusually robust, slightly 
curved, sub-cylindrical or fusiform spicules, with apparently rounded extremities, 
