38 On new Late Pleistocene Voles and Lemmings. 



pital breadth 14-0; occipital height (median) 6*8; breadth 

 of rostrum 5'9; nasal 8*7; diasteme 9'2 ; molar series 

 (alveolar) 7'4. 



Specimens examined. — One perfect and two fragmentary 

 skulls, together with a large number of lower jaws from the 

 Jghtham Fissures ; two or three maxillse with teeth and 

 numerous lower jaws from the Doneraile Cave, Co. Clare 

 (kindly lent by Dr. Scharff) ; and a maxilla from the 

 Langwith Cave, Derbyshire. 



Remarks.— The more reduced maxillary molar pattern 

 differentiates D. Tienseli from D. torquatus and its allies and 

 connects this species dentally with D. hudsonius. The latter 

 species is of larger size, but, apart from the agreement in the 

 teeth, the skull presents several points of similarity with the 

 fossil. It is distinguished principally by its expanded nasals, 

 rather broad and flat presphenoid, somewhat lighter teeth, and 

 slightly longer diasteme. The skull long ago described by 

 Hensel from the Pleistocene of Quedlinberg, in Saxony*, 

 appears to agree with that of the species here described, and 

 as that acute observer pointed out first the dental distinction 

 from D. torquatus], the species is here named in his honour. 



Dicrostonyx gulielmi, Sanford. 



"Arvicola" gulielmi, Sanford, Quart. Journ. Geol. Soc. vol. xxvi. p. 125 

 (1870) (name given to lower jaws from Somerset caves). 



Lemmas torquatus, var., Sanford, op. cit. pp. 124, 126 (skull from 

 Somerset caves). 



Specimens examined. — Anterior part of an adult skull and 

 many lower jaws in the collection of the Rev. E. Mullins 

 from the Langwith Cave, Derbyshire ; parts of two skulls, a 

 lower jaw, and detached teeth from a cave in the Wye 

 Valley, collected by Miss Dorothy Bate (now in British 

 Museum) ; and part of a youngish skull from Puy de Dome 

 Nescher (B.M.). f 



Characters.— Size large. Skull: nasals much expand e,. 

 in front, their combined width half the nasal length ; zye'ii 

 matic arches very heavy; palate boldly sculptured with 

 incomplete lateral bridges ; incisive foramina shor't and 

 broad; presphenoid reduced to a slender bar; tee^h very 

 heavy. 



Dentition : the posterior walls of the hinder inn**! triangles 

 in the first and second maxjUaiv-^Toiars not reduced, they 



* Hensel, Zeits. d. deutsch. geol. Ges. Bd. vii. p. 493, pi. xxv. figs. 12 



& 13 - , .-. -, 



t Ihid. Bd. viii. p. 279, pi. xan. tig. 1 a. 



