652 Mr. G. Dollaian on 



calcified tissue (fig. 1, .r) lying in tlie anterior angle of tlie 

 median dorsal plate a})pears to be merely a displaced i'ragraent. 



0£ the tail notiiing is preserved. 



From this description of the new specimen it is evident 

 that Psammosteus differs from Drepanaffpls at least in the 

 ficxibility of the lateral armour between the median dorsal 

 and ventral plates. It is possible also that the so-called 

 lateral spines of Psammosteus may bs movable appendages, 

 not homologous with any plates in P^rcpanaspis. The two 

 genera are therefore easily distinguishable ; but it would be 

 well to await the discovery of the head and tail of the Upper 

 Devonian fish before deciding whether or not to assign it to 

 a separate family. 



EXPLANATION OF PLATE IX. 



Psammosteus taylori, Traquair ; dorsal and ventral shields, with 

 appendages. — Upper Old Red Sandstone ; Newton Quarry, Elgin. 

 [WilUam Taylor Collection, Brit. Mus. no. P. 109o6.] 



Fig, 1. Inner view of dorsal plate, witli left side added from counterpart, 

 one-quarter nat. size, s., lateral spines ; a-, displaced fragment 

 of boue. 



Fig. 2. Dorsal view of mould of fossil, to show ventral plate in position, 

 one-quarter nat. size, d., internal mould of dorsal plate ; v., 

 inner lace of ventral plate. 



Fig. 3. Apex of left paired spine, enlarged by one-half, to show orna- 

 ment and worn border. 



Fig. 4. Small stellate tubercles of lateral region, enlarged by one-half. 



Fig. 5. Tossene of iufero-lateral region, enlarged by one-half. 



Fig. 6. Inner face of ventral plate, showing pustules, nat. size. 



LXXIT. — On neio Mammals from East Africa., presented to 

 the British Museum hy Mr. A. Blaney Percival. By GuY 

 DOLLMAN. 

 (Published by permission of the Trustees of the British Museum.) 



The following paper deals with some of the new mammals 

 contained in tlie large collection recently made by Mr. A. 

 Blaney Percival in East Africa. The greater part of the 

 collection has yet to be worked out, when a complete list of 

 all the specimens will be published. 



Elephantulus delicatus, DoUra. 



S. 435,436; ? . 424. 



A long-tailed species very similar in colour to E.somalicus, 

 Thos., but witii longer nasals and palate. 



