536 Mr. 0. Thomas on 



cells; per., peritoneum; pi/r.c, pyramidal cells; s.c, sensory cells; 

 s.d.ff., spermidiical glaud (prostate) ; Sep., septum 7/8 ; se^jt. and 

 se/ji.»?., septal membrane; s./., secondary funnel ; s./.', seta-follicle ; sh., 

 connective-tissue sheath round the dorsal yessel ; s.o., spermathecal 

 opening ; sp.b., sperm-blasts ; sp.c, spherical cells ; sp.d., spermiduct ; 

 sp.m., sperm-morula ; sp.s., sperm-sac ; si.l., shorter twisted lobe ; t.h., 

 tigroid bodies ; tc, testis-cells ; v., vesicle ; y.c, yolk-cells ; y.sp., yolk- 

 p'atelet.«. 



LT. — JSotes on the Species o/Notomys, the Australian 

 Jerhoa-rats. By Oldfield Thomas. 



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



The interesting jerboa-vats forming the genus Notomys liave 

 long been in a state of considerable confusion as regards the 

 species tliat exist, or, rather, have existed; for it is to be 

 feared that few of them still survive, except in the centre 

 and nortli of the continent. 



Wiien Central Australia was being explored under the 

 direction of Prof. Baldwin Spencer, a certain number of 

 specimens were obtained, and Mr. Waite published some 

 valuable notes on these *. He formed on them the groups 

 Poclanomahis and Thylac(>mys (which he afterwards renamed 

 Ascopharynx) ; but, as I have elsewhere f shown, these names 

 should be merged in the earlier Notomys of Lesson. 



The throat-pouch described by Mr. Waite appears to be 

 present in most if not all of the species, and would seem to 

 be a skin-gland, such as many rodents, bats, and marsupials 

 possess in a similar situation. Its use is probably of a 

 sexually attractive nature, and I cannot at all accept the 

 suggestion of ^Ir. Waite that the pouch might be of use for 

 storing food, as is the case with the American Geomyida^and 

 the European Hamsters. Its structure and general appearance 

 seem to me to precbade any such possibility. 



The two main causes of the confusion that exists as to the 

 species are, firstly, the publication by Gray of several names 

 without descriptions, and, secondly, the fact that Gould, who 

 liad an excellent hunter's knowledge of the forms dealt with, 

 knew nothing and gave no descriptions of the skulls, by 

 which alone the species can be satisfactorily determined. 



The following notes are based on a study of the series in 

 the British Museum, which contains specimens obtained by 



* P. Roy. Soc. Victoria, (2) x. pt. ii. p. 117 (1898). 

 t Ann. & Mag. Nat. Hist. (7) xvii. p. 83 (1906). 



