On a new Leptolepid Fish from the JVeahi Clcuj. 93 



XVIT. — On a new Leptolepid Fish from the Weald Clay of 

 Southioater, Sussex. By A. SMITH WoODWARD, LL.D., 

 F.R.S. 



[Plate I.] 



Thin cycloid scales which might have belonged to a Leptolepis- 

 like fish have already been noticed in the English Wealden 

 formation, bat no complete example of a Wealden member 

 of the Leptolepidee has hitherto been described. A well- 

 preserved specimen, however, which may be referred to the 

 family just mentioned, lias lately been found in the Weald 

 Clay at Southwater, near Horsham ; and I am indebted to 

 the Directors of the Southwater Brick and Tile Co., Ltd. 

 (through Mr. C. H. Aldersmith, A.M.I.C.E.), for the oppor- 

 tunity of studying this interesting fossil, which has now been 

 presented to the British Museum. 



The new specimen is preserved in counterpart in a slab of 

 clay, and its best half is shown of one half nat. size in 

 PI. I. fig. 1. It is exhibited in direct side-view, only 

 lacking the anterior part of the head and the hinder half of 

 the caudal fin. The maximum depth of the trunk is con- 

 tained somewhat less than three times in the length from the 

 pectoral arch to the base of the caudal fin, and would probably 

 equal about one fifth of tlie totr.l length of the fish. The 

 same depth is not quite three times as great as the depth of 

 the caudal pedicle. The fragmentary remains of the head 

 show that the mandibular suspensorium is inclined forwards, 

 so that the articulation of the lower jaw must have been 

 directly beneath the hinder part of the orbit. The hyo- 

 mandibular bone [hm.) bears a long process for the suspension 

 of the operculum {op.), which is shown in impression, trape- 

 zoidal in shape, and about as deep as broad. The preoper- 

 culum {pop.) has a long upright ascending limb, expanding 

 below into a triangular plate. The suboperculum {sop.), best 

 seen in the counterpart not figured, must have been about 

 four times as broad as deep. Fifteen branch iostegal rays {br.) 

 can be counted, the upper seven being expanded and in close 

 series, the lower eight being narrower bars and more widely 

 spaced. The opercular apparatus is quite smooth, not 

 ornamented. The total number of vertebrce is about sixty, 

 half being in the abdominal region. The centra arc about 

 as long as deep in the anterior part of the caudal region, but 

 are somewhat shorter than deep both in the abdominal and 



