CHAP. IV] THE GENERAL ANATOMY OF THE TARSII 93 



exactly the converse of that obtaining in Man. The relation of 

 the right kidney to the caudate lobe of the liver has been noted 

 above. Beside the liver (and the adrenal body) the duodenum 

 and colon touch the right kidney, the duodenum being placed 

 further from the mid-line than the colon, and herein again the 

 contrast with the human arrangement is striking. The testes 1 

 occupy a scrotum either alongside or just posterior to the root 

 of the penis. The scrotal sac is provided with a " cremaster " 

 muscle derived from the M. transversalis abdominis. 



The penis contains a simple rod-like bone developed on the 

 dorsal aspect of the urethra (by which it is not perforated as 

 in some forms) in the free part of the organ. The free part of the 

 penis is further characterized by an armature of thorn-like and 

 horny excrescences, and of these three near the base of the penis 

 are larger than the others and are directed proximally (analogous 

 spines are described in the rodent Dipus or Jerboa). 



A definite corpus spongiosum distinguishes the true Lemurian 

 urethra from that of Nycticebus. In most of the above characters, 

 the " true " Lemurs are the most primitive of all the Lemuroidea. 



The bladder is of the primitive " tubular " form. 



The sperm-cells 2 (Fig. 51) are distinguished by (a) the great 

 length of the pars conjunctions (Verbindungsstuck) containing 

 the centrosomes; (6) the great relative width of the nuclear 

 portion of the head. Of these characters, the first is more constant 

 than the second among the Lemuroidea. 



In the female Lemur, the Fallopian tubes are short, though 

 coiled : the clitoris is of very considerable size :i . 



II. Tarsii. 



The anatomical characters of Tarsius have led authorities 

 of great distinction to regard it as the most primitive of all 

 living Primates. Such an animal commands a very special interest. 

 I think it desirable to remark that the possession of characters 

 testifying to the conclusion formulated above, is quite compatible 



1 From the descriptions of Kaudern, Zoologuchc Jahrbucher, 1910. 



2 Retzius, Biologische Untersuchungen, N. F. Band xiv. 1909; also Band xvn. 

 1912. 



3 Patten, op. cit. 



