DR. G. J. HINDE ON RECEPTACULITIDA. 839 
Iscuapires Linpstrami, Hinde, n. sp. (Pl. XXXVI. fig. 2.) 
Cf. Ischadites Grindrodi? Salter, MS. (see Bigsby’s Thesaurus 
Siluricus, p. 4). 
Sponges with wide bases, markedly concave in the centre, and 
with apparently low conical summits. The specimens vary from 
50 to 100 millim.in diameter. The spicular surface-plates vary from 
3°5 to 5 millim. in greatest width. No summit has been preserved. 
This species differs from J. Kenigit in its considerably larger 
dimensions and the larger size of the summit-plates. I cannot say 
whether it is the same as the J. Grindrodi, Salter, MS., since there 
is no description or figure of this species. Some specimens of this 
species in the Jermyn Street Museum are labelled, but not by Salter, 
I. Grindrodi, whilst others precisely similar bear the label of J. 
Kenigii. It seems best therefore, in the abseuce of definite know- 
ledge of the type of Z. Grindrodi, to adopt another name, and I 
propose to name it after Prof. G. Lindstrom of Stockholm, to whom 
T am indebted for the loan of the specimens. 
Distribution.— Wenlock shale: Malvern, Lower Ludlow, Ledbury; 
lowest beds of the Silurian: Petesvik, Hablingbo, isle of Gotland. 
IscHADITES TESSELLATUS, Winchell and Marcy *. 
1866. Ischadites tessellatus, Winch. and Marcy, Mem. Bost. Soe. 
Nar bise. vol. i. pt. I, p. So, t. 2. fig. 3. 
Non J. tessellatus, Salt. MS., Siluria, 4 ed. 1867, p. 509. 
1870. Receptaculites formosus, Meek and Worthen, Proc. Ac. Nat. 
Sc. Phil. p. 23. 
1875. Receptaculites formosus, Meek and Worthen, Pal. Illinois, 
Vol. vi. p. 500, t. 24. fig. 1. 
1875. Ischadites tessellatus, Giimbel, Beitr. p. 40. 
The specimen figured is the cast of the lower portion of an 
apparently pear-shaped individual with a conical base. The rhom- 
boidal spicular plates are from 2°5 to 5°5 millim. in width. According 
to the author some examples are 62 millim. in height by 43 in width, 
and thus considerably larger than J. Kenigw, whilst the general 
form distinguishes the species from J. Lindstremi., 
Meek and Worthen figure a perfect example of this species under 
the name of Ff. formosus. Its correspondence in form and the fact 
of its being derived from the same geological horizon and locality 
place its identity with this species beyond doubt. 
Distribution.—Silurian: Niagara limestone, near Chicago, Illinois. 
* According to Miller’s ‘Catalogue of American Palzozoic Fossils’ (1877), 
p. 43, this species is a synonym of Receptaculites infundibulus, Hall, Geol. Re- 
port Wisconsin, 1861. I have been unable to obtain a copy of Hall’s paper 
either in the library of the Geological Society or in that of the British Museum. 
I may say that in the absence of figures, mere verbal description, like Hall’s, 
of the fossils of this group, is quite insufficient for the recognition of 
species, more particularly when the character of the fossil is so little understood 
by the author that he regards the base of the fossilas its summit, and vice versd. 
Meek and Worthen (Geol. Illinois, vol. ili. p. 302) similarly express their ina- 
bility to recognize Hall’s species of this genus in the absence of figures, and 
there are therefore sufficient grounds for rejecting the species described in this 
paper unless subsequently verified and figured by the author or other writers. 
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