28 THE ZOOLOGIST. 



considered. The principal generic characters were the perforation of the 

 gill-septum, found also in Arnoglossus megastoma, and the prolongation of 

 the dorsal and ventral fins on to the right side at the base of the tail. The 

 marked peculiarity of habit was that of adhering to vertical surfaces. It 

 was shown that this was independent of either of the characters mentioned, 

 and was due to the pumping-action of the longitudinal fins and their muscles 

 posteriorly, the enlargement of those parts being also a generic character. 

 No evidence of the utility of the specific characters could be discovered. 

 The characters of other Pleuronectidce were similarly examined, and the 

 conclusion reached was that there are two kinds of characters, the adaptive 

 and the morphological. 



Mr. A. Smith Woodward read a description of the so-called Salmonoid 

 fishes of the English Chalk, dealing with the osteology of Osmeroides 

 lewesiensis, Elopopsis crassus, and Aulolepis typus. He directed special 

 attention to three features in the head of the genera to which these species 

 are referred, namely : (1) the exclusion of the supraoccipital from the cranial 

 roof by the union of the parietal bones in the median line ; (2) the over- 

 lapping of the arched maxilla by two large supramaxillary bones; and 

 (3) the presence of a large gular plate. All these characters separated the 

 fishes in question from the typical Salmonidce, while the first and third 

 distinguished them from typical Clupeidce. All three genera should be 

 associated with the existing Elops, Megalops, and their allies. 



Mr. W. Garstang read a paper on the Gastropod Colpodaspis pusilla of 

 Michael Sars, describing a specimen of this rare mollusc found by him at 

 Plymouth in the early part of the year. (See p. 25.) 



A communication from Mr. A. D. Bartlett gave an account of the recent 

 occurrence in the Society's Menagerie of a case of one Boa swallowing 

 another of nearly equal size. 



A communication from Prof. K. Collett contained a description of a new 

 Agonoid fish from Kamtschatka proposed to be called Agonus gilberti. 



Dec. ith. — Henry Seebohm, F.L.S., F.Z.S., Vice-President, in the 

 chair. 



The Secretary read a report on the additions made to the Society's 

 Menagerie during the month of November, and called attention to the 

 Surinam Water-Toads, Pipa americana, presented by Mr. F. E. Blaauw ; 

 to a fine example of Pels' Owl, Scotopelia peli, from Sierra Leone, presented 

 by the Hon. C. B. Mitford, Deputy-Governor of the Colony ; and to two 

 Tree-Kangaroos from Queensland, received in exchange. 



A communication was read from Mr. T. Manners Smith on some points 

 in the anatomy of the Water-Mole, Ornitliorhynchus paradoxus, relating 

 chiefly to the muscular anatomy and the trunk-arterial system. 



Mr. F. E. Beddard read a paper on certain points in the visceral anatomy 

 of the same auirnal. 



