BY E. J, GODDARD. 483 



paucis, longis vero fortibusque dentibus armatse." The arrange- 

 ment and nature of the teeth may be seen in fig. 10. 



The only internal structures which call for any special remark, 

 are the reproductive organs. 



The testes lie in the last annular region of somites xii.-xxi., 

 that is, in the second annulus behind the nerve-ganglia of these 

 pentannulate somites. There are present ten pairs, as in most 

 species of Hirudo. In H. medicinalis there are nine pairs 

 normally present, but occasionally one finds ten pairs. In Parker 

 and Haswell's diagrams there are only nine pairs represented in 

 connection with H. quinquestriata. It is quite possible that nine 

 pairs may sometimes be present in our form, although I have 

 dissected a large number of specimens, and have never reckoned 

 less than ten pairs. At first I imagined that, very possibly, if 

 H. australis and H. qitinquestriata were not synonymous, that 

 the former might possess nine pairs and the latter ten pairs. 

 However, such I am sure is not the case, and, as it is well nigh 

 impossible that one would miss one pair when making a count of 

 such conspicuous organs in a dissection, it seems very possible 

 that nine pairs only are present as an occasional variation in 

 Limnohdella australis. 



Benham notes the presence of ten pairs in H. mauiana, and 

 only seven pairs in //. antipoduin. 



In consideration of these facts, it would seem that we must 

 regard the genus Hirudo as being originally provided with ten 

 pairs of testes, and that this number has later shown a tendency 

 towards reduction. It is apparently the last pair of testes, as 

 represented in Limnohdella australis^ which is generally absent 

 in Hirudo medicinalis. 



The ovaries agree in nature with those of other species, and 

 call for no special remark. 



The male ap))aratus agrees with that of //. mauiana, in having 

 a strong muscular sac between the anterior extremity of the 

 seminal vesicle and the "prostate." The vasa defereatia pass- 

 along the outer side of the testes, with which they are connected 

 by a delicate vas efferens in the last annulus of each testigerous 



