1894.] SO-CALLED SALMONOID FISHES OF THE ENGLISH CHALK. 655 



Angora Eabbit which had shed its entire coat in one piece for two 

 years in succession. This seemed to show an analogy in a mammal 

 to the simultaneous moulting of certain birds. 



Sir William Flower exhibited a specimen of a Hairy Armadillo 

 (Tatusia pilosa), obtained by M. J. Ivalinowski in the Maraynioc 

 district of Central Peru. It had been acquired by the British 

 Natural History Museum in exchange from the Branicki Museum, 

 Warsaw, through the kind offices of Dr. Stolzmann. In dimen- 

 sions and other characters it exactly resembled the specimen 

 belonging to the Scarborough Museum, that Sir William Flower 

 had brought before the Society on November 16, 18S6 (see P. Z. S. 

 1886, p. 419), which was identified with Cryptophractus pilosus 

 of Pitzinger (32 te Versamml. deutsch. Naturf. u. Aerzte, 1856, 

 Tageblatt Xo. 6, S. 123), and with Praopus Mrsutus of Burmeister. 



A communication from Mr. J. T. Cunningham treated of the 

 significance of diagnostic characters in the Pleuronectidse. In this 

 paper the specific and generic characters of the so-called Top-knot 

 (Zeugopterus) were first considered. The principal generic cha- 

 racters were the perforation of the gill-septum, found also in 

 Amoylossus 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 pum ping-action of the longitudinal 

 fins and their muscles posteriorly, the enlargement of these parts 

 being also a generic character. Xo evidence of the utility of the 

 specific characters could be discovered. The characters of other 

 Pleuronectidae were similarly examined, and the conclusion reached 

 was that there are two kinds of characters, the adaptive and the 

 morphological. 



The following papers were read : — 



1. A Description of the so-called Salmonoid Pishes of the 

 English Chalk. By A. Smith Woodward, F.Z.S. 



[Keceived November 6, 1894.] 



(Plates XLII. & XLIII.) 



It is remarkable that among British fossils many of the 

 commonest and most typical species have been the least satis- 

 factorily studied and described. Among fishes this is more 

 especially the case, and none have received less attention than 

 those of the English Chalk. Some of them, such as the so-called 



