i 7 4 SOME ETHIOPIAN REPTIIES, FISHES, AND INVERTEBRATES 



common. To Calcutta it was introduced about half a century ago, and by 1877 

 was abundant in the gardens of the houses in Chouringhi, while it had also crossed 

 the Hughli to Howra and Barrakpur. About ]900 a collector introduced the 

 species on his estate in the highlands of central Ceylon, but soon after attempts 

 were made to exterminate the intruders, and it was believed effectually. It appears, 

 however, that some escaped destruction, and of these a couple were carried down 

 with vegetables to the low country. Here they increased to such an amazing 

 extent, over an area of about five square miles, that in 1910 their numbers were 

 to be reckoned by millions, no fewer than 227 being counted in a cluster on the 

 stem of a cocoanut palm in a length of about 6 feet. Naturally the natives were 

 in fear that their crops would be devastated ; but, as a matter of fact, little or no 

 serious damage was inflicted, and it appears that the species largely acts the part 

 of a scavenger, so that in some degree, at any rate, its introduction was a benefit. 

 The adults are attacked by a terrapin of the genus Nicoria, and in its young 

 stages the species probably has many foes. The enormous fecundity of these snails 

 on their first introduction to the lowlands was probably a temporary phenomenon, 

 and their numbers soon began to diminish. 



In the great lakes, as well as in many of the rivers, molluscs, both univalve 

 and bivalve, are abundant. Among the univalve types furnished with an oper- 

 culum to the mouth of the shell, the genera Lanistes, Cleopatra, and Meladomus 

 are exclusively Ethiopian ; the same being the case among bivalves with the genera 

 Mutela and JEtheria in the river-mussels (Unionidce) and with Galatea and 

 Fischer-ia in the Cyrenidce. Although the fresh- water snails of the great equatorial 

 lakes are for the most part more or less nearly related to those from other regions, 

 the molluscan fauna of Tanganyika affords a very remarkable exception in this 

 respect. In addition to the ordinary fresh-water types, this lake is the home 

 of a number of snails whose shells present a curious superficial resemblance to 

 those of certain extinct genera of marine gastropods. These have been, somewhat 

 hastily, regarded as remnants of an ancient marine fauna — the so-called halolymnic 

 fauna— which have been cut off from the sea and gradually accustomed to a fresh- 

 water existence. Examination of the soft-parts has, however, shown conclusively 

 that these remarkable genera are nothing more than aberrant types intimately 

 related to more ordinary fresh-water snails. The reason for their abnormality in 

 the matter of shell-form still awaits an explanation. 



The slugs of South Africa, as specialty exemplified by those of Natal, include 

 a considerable number of species, arranged in six families, of which the Aperaidce 

 is represented by the exclusively South African genus Apera. Of the rive species 

 of this remarkable genus, which was formerly included in the Testacellidce, three 

 are found in Natal. The genus is believed to represent a primitive type, such 

 resemblances as it shows to the Testacellidce being probably due to parallel develop- 

 ment. It was originally described as Chlamydephorus, a name clashing with 

 Cldamydophorus, the title of the fairy armadillo of South America. 



The large bodily size attained by many members of the Ethiopian 

 Insects. c . . 



fauna is further exemplified in the case of the goliath beetles of the 



west coast. In the ordinary grey goliath (Goliathus druryi) the males, which are 



velvety black in colour with chalky white markings, attain a length of 4 inches. 



