4 Prof. E. Ehlers on Lepidosiren paradoxa and 



the tip of the snout, the entire cephalic portion of X. artieidata 

 appears longer than that of L. paradoxa. The occipital 

 region in the latter is more strongly arched than in L. articn- 

 hita ; the profile of L. jparadoxa consequently makes a more 

 marked descent towards the tip of the snout than does that of 

 L. articulata, whereby the head of Lepidosiren paradoxa 

 acquires the sharper conical form which is seen in the figures 

 of Natterer, Bischoff, and Castelnau. This is especially 

 evident if the heads of the two fishes are compared together 

 when looked at from above. Lepidosiren paradoxa then 

 appears to have a pointed snout, since the portion of the head 

 lying in front of a line connecting the eyes is sharply conical, 

 while the less narrowed snout of L. articuJata is bluntly 

 rounded. These differences in the shape of the head, which 

 are occasioned by the conditions of the skeletal parts, are 

 accordingly to be regarded as constant. 



The measurements quoted above show a difference between 

 the two species in the size of the extremities, the posterior of 

 which exhibits a sexual dimorphism in each case. But no 

 great value is to be attributed to these differences, since the 

 size of the extremities appears to vary, and is influenced by 

 injuries which afterwards heal up. The extremities of 

 I^epidosiren paradoxa are in general longer and more slender 

 than those of L. articulata ; in both species the posterior 

 appendage is stronger than the anterior, and in it the difference 

 between the two species is especially evident, since in L. ar- 

 ticulata it is generally stouter than in Lepidosiren paradoxa^ 

 in which it is of a slender conical shape. Tlie anterior extre- 

 mities of Lepidosiren aiticulata were generally flattened and 

 furnished with a slight marginal border. This was not so 

 strongly marked in those of Lepidosiren paradoxa. The 

 posterior extremities of the males of L. articulata are longer 

 and thicker than in the females of the same species, and also 

 are probably thicker than those of L. paradoxa. What 

 is more striking than anything else, however, is that while 

 in the females of L. articulata the posterior extremities are 

 perfectly smooth, as they are also represented in the figures 

 of the female of Lepidosiren paradoxa, in the case of the male 

 animals these appendages bear upon the median and dorsal 

 region a thick growth of close-packed pale-coloured papilla?, 

 of a flattened leaf-shaped form, which are set in tufts upon a 

 common base. These papilla? were most strongly developed 

 in the largest specimens, where they formed a thick brush- 

 like coat, which, with the exception of a short basal area, 

 extended over the entire length of the appendage. In other 

 specimens only a median portion of the extremity was 



