THE 



GEOLOGICAL MAGAZINE 



NEW SERIES. DECADE III. VOL. IV. 



No. VIII.— AUGUST, 1887. 



OK,IG-IlsrJ5>.Xj .A.I?,TIOLE!S. 



I. — On New Species of Pholidoprorus from the Purbeck Beds 

 OF Dorsetshire. 



By "William Daties, F.G.S., 

 of the British Museum (Natural History). 



(PLATE X.) 



FEW genera of Fossil Fishes contain so large a number of well- 

 defined species as Agassiz's Avidely-distributed and well-known 

 genus PhoUdophorus. Above forty species have been more or 

 less fully described by Agassiz and subsequent authors ; the geologi- 

 cal range extending from the Eh^tic to the Purbeck Beds inclusive. 

 The group consists mainly of small or moderate-sized fishes, but few 

 that can be termed large ; and with the exception of one species (P. 

 maximus),^ the generic identity of which is doubtful, it contains no 

 fishes of magnitude. Fifteen species have hitherto been recorded as 

 occurring in British rocks by Agassiz^ and Egerton^ respectively, the 

 geological distribution being as follows: — Two species from theRhEetic 

 Beds at Aust ; nine from the Lower Lias (Lyme Eegis ; Street ; and 

 Barrow-on-Soar) ; one species from the Inferior Oolite of Blisworth ; 

 one from the Great Oolite, Stonesfield ; and lastly, two from the 

 Purbeck Beds of Swanage, namely Pholidopliorus ornatus, Ag., and 

 P. grnnulatus, Egert. These last are fishes of moderate size ; with 

 crenulated and otherwise ornamented scales. The fishes which form 

 the subject of this article differ in some important characters from 

 the above-named species ; inasmuch that they are diminutive in size, 

 have smooth unornamented scales with entire free margins, another 

 feature being the reduced number of the vertical series covering the 

 flanks. They are apparently rare, the specimens here described 

 being the only examples that have come under my observation. 

 They comprise two forms, one short and deep, the other more 

 elongate. 



Pholidophoeus purbeckensis, sp. nov. (Plate X. Fig. 2.) 



This species is founded upon two specimens, one in the j)rivate 

 cabinet of Mr. Damon, of Weymouth, who has kindly submitted it 

 to me for examination, the other on counterpart slabs in the National 

 Collection (B.M. 40635). They are elegant fusiform fishes, less 



^ Agassiz, "Eech. Poiss. Foss." torn. ii. p. 287. 



^ Vp. cit. torn. ii. 3 Mem. Geol. Surv. Decades vi. and viii. 



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