386 The Penis-hone, or " Baculum,^^ in certain Squirrels. 



For tyjDe I would select Tomeutes lokroides {Sciurus lok- 

 roides, Hodgs.), and, so far as can now be ascertained, the list 

 of the chief species would be as follows, arranged, as before, 

 into verified species, in the first column, and consequential 

 species in brackets : — 



Tomeutes lokroides. 



,, siviilis. 



,, jj/iap-ei. 

 „ blanfordi. 



„ pyyeri/thrus, 



„ janetta. 



,, piypi-i (hippurus group.) 



„ philippinensis (steerei, juvencus.) 



„ melanogaster {alratus.) 



„ tenuis {pumilus, fruterculus, and many 



others.) 

 „ brookei. 

 „ luwii. 



„ mnrinus. 



It is to be hoped that by decrees tlie bacular characters of 

 the remaining Oriental squirrels may be ascertained, for their 

 skulls and teeth often give little clue to their proper situation. 

 Unfortunately in preparing dry specimens the skin of the 

 penis readily slips off, and the baculum is thrown away with 

 the carcase, unless the collector has been specially told to 

 save it. The majority of the bacula I have been able 

 to secure, apart from a number carefully preserved by 

 Mr. Shortridge, have been extracted from spirit-specimens. 



I may note that Mr. Shortridge tells me that, so far as ho 

 Las seen, the species I have put into T'omeutes are, on the 

 whole, more terrestrial in their habits than those of Callo- 

 sciurus, although there are a few exceptions. 



In the preliminary study of this subject that I have so far 

 been able to make, a few points stand out very clearl3\ 



Firstly, the wide, or at least absolutely complete, separation 

 of the forms with compound bacula as compared with all 

 the other Sciuridge, and their comparatively near relationship 

 to each other. Consequently the separation of the Nanno- 

 sciurinse as a subfamily set over against other squirrels is 

 flatly contradicted by the 2hmeutes-\\k.e bacula of the type- 

 genus, with but little special peculiarity. (The edge of the 

 blade in JS^. white/ieadi is beautifully serrated, but this is 

 not the case in certain other species.) 



The presence of a simple baculum in Myosciurus minutus, 

 which is therefore after all not related to the Malayan Nanno- 

 sciurus, and is further evidence of the invalidity of the 

 " Nannosciurinse " as a subfamily. 



