44 Dr. G. J. Hinde on Radiolaria from the 



four primary radial spines, some with, some without an inner 

 or medullary test, are also common (PI. III. fig. 6, PI. IV. 

 figs. 2, 4-7, 9-11) ; the structure of these appears to be uni- 

 formly of the irregularly reticulate or spongy character. The 

 spines in some of these shells are of unusual length (PI. IV. 

 figs. 2, 9), but it is very rare to meet with specimens in which 

 they all remain intact. There are also a few specimens with 

 lattice tests and numerous smaller spines (PI. IV. fig. 1) 

 included in the well-known recent genus Acanthosphcera, 

 Ehrenberg, and others with larger spines (PI. III. fig. 11, 

 PI. IV. fig. 8) which I have referred to Haliomma. 



In addition to the above, mention may be made of some 

 peculiar spicules (woodcut, p. 56, i, k, I) of the same general 

 characters as the Beloid forms already referred to, which seem 

 to correspond to the spisular skeletons of some existing 

 Radiolaria, which are regarded by Ilreckel as the simplest 

 and most primitive types of the great primary division ot" the 

 Kassellaria, in which they form the distinct subDrder Plec- 

 toidea *. The spicules in question consist of a variable 

 number of simple or branched arms or rays proceeding from 

 a centre ; the rays may be either free or connected by irregular 

 fibres with each other. Spicules of this type are rare and 

 not often entire, and their true position is not altogether free 

 from doubt. 



These Palaeozoic Radiolaria, so far as can be judged from 

 their present condition, do not differ in any striking respect 

 from the existing forms of the group or from those numerous 

 fossil ones which have been lately described by Dr. Riist f 

 and others from Jurassic and Cretaceous strata. Some of the 

 more peculiar forms with one or with three primary radial 

 spines bear a close resemblance to specimens figured by v. 

 Dunikowski % from the Lower Liassic strata of Schafberg, in 

 the Tyrol. The detached spicules of the Beloidea have like- 

 wise been noticed by Riist in the Radiolarian Jurassic strata 

 of the continent. The quantity of this ancient chert which 

 has as yet been examined is too small to permit of any general 

 deductions as to the characters of the Radiolaria contained in 

 it ; but it is noticeable that so far, if we except the iaw 

 spicules doubtfully referred to the Nassellarian Plectoidea, the 

 forms belong to only two divisions of the Spumellaria, the 

 Beloidea and the Sphajroidea j and there is an apparent 

 absence not only of the discoidal and elliptical forms of the 



• Chall. Report, pt. ii. p. 890, pi. xci. 



t ' rahvoutujifinphica," Jid. xxxi. ^188o), Bd. xxxiv. (1888). 

 X Deukscbr. d. k. Akad. d. \Niss. Wien, Bd. xlv. (1882), pp. 187, 188, 

 Taf. V. Hgs. 53-55, 59. 



