110 8. H. Reynolds — Lower PalcBozoic fossils of Yorkshire. 



1. The glabella bears only two well marked tubercles, and these 

 are arranged in a line with the axis. 



2. The cheeks each bear a single tubercle. 



3. There is no evidence as to the occurrence of cheek spines. 



4. The margin of the axis is tuberculate. 



5. The pleurae of the middle thoracic segments are longer than 

 those of the posterior thoracic segments. 



D. HugJiesiae differs from D. Frederici Augusti, Barr., in having 

 two instead of one tubercle on the glabella and one on each cheek, 

 also in having the pleurse much longer and non-tuberculate. 



It differs from D. Saidingeri, Barr., which comes decidedly near 

 P. ornata in having more tubercles on the glabella and in the 

 greater length of the pleurse of the middle thoracic segments. 



D. Cordai, Eth. and Nich., differs from D. Hiighesiae in having a 

 pyriform glabella without tubercles. 



Note. — I have had to rely only on figures and descriptions in 

 comparing D. Hughesiae with the other species. 



Note on a Cystidean ? Ateleocystites. 

 (PLATE IV. Figs. 9 and 10.) 

 This specimen was found in the Bala beds of Wharfe by Eev. A, 

 Pagan. It is unfortunately not well preserved, but appears to differ 

 considerably from any known cystidean. It appears to belong to 

 the family Anomalocystidce (H. Woodward) and to agree with the 

 other forms figured by Dr. Woodward in the Geol. Mag. 1880, 

 p. 193, in the following characters : — 



1. The plates are not arranged with complete regularity. 



2. The anterior surface is slightly concave. 



3. There are no pectinated rhombs. 



4. The plates are marked by a finely wavy ornamentation. 



It differs from other Anomalocystidce in the ornamentation of the 

 plates and in the apparent greater irregulai'ity in their arrangement, 

 though this may in part be due to crushing. 



The way the arrangement of the plates is to be interpreted is not 

 very clear, but regarding the face preserved as the anterior face, 

 the plates of the upper (oral) surface and right side are well pre- 

 served, while those of the left side and lower surface (from which 

 the stem would arise) are more broken. The uppermost median 

 plate is characteristic and is marked by 5 or 6 ridges radiating from 

 a raised point near the margin. All the plates are marked with the 

 wavy lines characteristic of the Anomalocystidce, and in addition are 

 marked by a series of rather deep pits sometimes arranged in lines. 

 These pitted markings are better seen on the impi-ession than on the 

 actual fossil. The markings somewhat resemble those on Turrilepas. 

 A segment of the stem is also seen. 



EXPLANATION OF PLATE IV. 

 Fig. L — Dindymene Hughesiae, Roberts, MS. ; pygidium and posterior thoracic 

 segments, x 3^. 

 ,, 2. — Enerinurus punctatus, var. arenaceus, Salt. ; glabella and fixed cheeks. 



X 6. 

 ,, 3. — Staic7'ocejphalus, ci. Murchisoni, Ba,ii. ; part of head. x 6. 



