Royal Physical Society. 21 



trials, the Upper jaw slightly projects over the under. In this species the 

 reverse is the case, the lower jaw projecting decidedly (though not very far,) 

 in advance of the upper. The barbule on the upper jaw of if. electricus 

 is a third shorter than the head ; Beninensis has it longer than the head. 

 In the former the gill-opening terminates at the lower edge of the pectoral 

 fin, in the latter the pectoral fin is attached at the middle of the gill- 

 opening, and its lower edge does not nearly reach the "base of the gill- 

 opening. It will also have been seen that there are some differences in 

 the relative proportion of the different parts of the two fishes, and there 

 are also some other differences in the form of some parts of the fishes 

 (such as the operculum) which are not so readily embodied in words, but 

 the differences which will most easily enable them to be distinguished at 

 a glance are the markings, if these shall be found to be constant. The 

 spots on M. electricus are much larger and more numerous than on this 

 species, and it entirely wants the white bands across the tail, and across 

 the caudal fin, which were described by Mr Murray.* 



III. Mr Murray exhibited a collection of Coleoptera, which he had re- 

 ceived from Mr Jameson, Professor of Chemistry at Quito. Among these 

 were Oxychila bipustulata, Phanceus conspicillatus, Semiotus impe- 

 rialis, and other known Columbian species, but a number were new to 

 him, and apparently undescribed. 



Mr Murray also exhibited a few Coleoptera, taken by his friend Cap- 

 tain Macneill, of the 20th Regiment, in the camp before Sebastopol during 

 the past winter. These included fine specimens of Hammaticherus heros, 

 Lucanus serricomis, and some other species, which, besides their beauty 

 and rarity, possessed an additional interest from the locality and circum- 

 stances in which they were collected. 



IV. Anatomical details of the new species of Malapterurus. 

 By Professor Goodsir. 

 Professor Goodsir stated, that as he had only received the specimen of 

 Malapterurus a day or two before the meeting, it was impossible for him 

 to do more than merely make a few remarks on the subject. He would, 

 however, be glad to give a detailed communication to the Society next 

 session, after he had made a careful dissection of this very interesting 

 fish. The Professor then, after reviewing shortly the results of Pacini's 

 recent examination of the electrical organs of Torpedo, Gymnoius, and 

 Malapterurus, and his own examination of the presumed electrical organ 

 in the tail of the skate, discovered by Dr Stark, and subsequently described 

 by Robin, stated that, so far as his own dissection had proceeded, the struc- 

 ture of the specimen of Malapterurus, for which he had been indebted to 

 Mr Murray, corresponded to the description of Pacini, with the exception of 



* Since Mr Murray's paper was read he has received older and larger speci- 

 mens from Old Calabar, from which he finds that these white bands disappear 

 in the full-grown fish. 



