22 EINAR LÖNNBERG, ANATOMICAL NOTES ON EAST AFRICAN MAMMALS. 



With regard to the number of rows in which the cotyledons are arranged Re- 

 dunca occupies an isolated position with only two rows. Gonnochcetes has tive, and 

 all the others four. 



With regard to the number of cotyledons found in each cornu of the uterus 

 two different types can be discerned. In one the number is subequal in both cornua 

 as in Eland, Grant's Gazelle, Reedbuck, and YVhite-tailed Gnu. In the other type 

 the number of cotyledons in one cornu is twice, or more than twice, as large as in 

 the other. This condition has been found in Impala, Suni Antelope, Wroughton's 

 Dik-dik (in the greater number of cases), Ogilby's Duiker, and the Red Forest Duiker. 

 When this latter condition prevails it is, of course, the gravid cornu which contains 

 the greater number of cotyledons. The question arises now whether such a condition 

 with unequal number of cotyledons in the two cornua is a constant character, or not. 

 Against its being constant speaks the fact that in one Dik-dik out of three the 

 number was equal, in the two others unequal, but on the other hand in four other 

 additional species the number was found to be unequal. If the latter condition should 

 be normal and constant in some species of Antelopes, it could be concluded that in 

 such species only one cornu, viz. the one with the greater number of cotyledons 

 would be normally pregnant. This appears perhaps at first somewhat stränge but 

 this impression will disappear if the observed facts are studied more closely. All 

 Antelopes of which I have obtained gravid specimens for this investigation — even 

 those with a subequal number of cotyledons in both cornua — have had the foetus in 

 the right cornu. The same was after reexamination also found to be the case with 

 a Cephalophus ogilbyi and a Redunca arundinum. This proves that among Antelopes 

 generally it is at least more usual that the right cornu becomes gravid than the 

 left. For the same may also speak that in a not gravid Grant's Gazelle the right 

 cornu was larger than the left. In Ellenbergkr and Muller' s manual it is stated 

 that in common cattle in 60 percent of cases it is the right uterine cornu which 

 contains the foetus, although in these animals both cornua have a subequal number 

 of cotyledons. The prevalence of the right cornu, as mentioned above. stånds naturally 

 in connection with the fact that in Ruminants it is less pressure (from the paunch) 

 and more space for the growth of the gravid uterus on the right than on the left 

 side of the abdominal cavity. Considering all this, it does not appear at all impos- 

 siblc that in some species it has become quite a constant feature that only the right 

 cornu is the one in which the foetus normally is developed, and as aresultof this, the 

 flinet ions of the left are diminished, and the number of its cotyledons consequently 

 reduced. 



If this hypothese is correct the above mentioned specimen of Rhynchotragus 

 guentheri wroughtoni with a subequal number of cotyledons in both cornua would 

 exhibit rathei an anomaly for the species, although it represents the original state 

 of affairs. Such an anomaly would then be explained by assuming that in tliis in- 

 dividual the lefl cornu contrary to the rule had been impregnated at the first con- 

 ception, and consequently developed when the animal for the first time became gravid. 



