338 William Davies — New Purbeck PJiolidophorus. 



than 3| inches (85 mm.) in length. Unfortunately the head in each 

 specimen is so much crushed, that, with the exception of the oper- 

 cular plates, the component elements are too indistinct for separate 

 description; but its form and relative proportions are fairly well 

 preserved. The orbits are of moderate size ; the operculum is 

 oblong, the upper margin being slightly convex, and the sub-oper- 

 culum is triangular in form. The head forms one-fourth of the 

 entire length of the fish, and is equal to the depth of the body a 

 little in advance of the ventral fins. The scapular arch is nearly 

 concealed by the opercular plates. The paired fins are imperfect, 

 a few rays of each only being preserved, which suffice to indicate 

 their position. The ventrals are placed midway between the attach- 

 ment of the pectorals and the anterior ray of the anal fin. The 

 latter fin is also imperfect, insomuch that the distal bifurcated 

 extremities of the rays are wanting. It consists of ten strong and 

 unarticulated rays, and is 9 mm. in length ; no fulcral scales are 

 preserved on either specimen. The dorsal fin rises from the middle 

 of the back and opposite the interspace dividing the anal and ventral 

 fins. It is short but incomplete, the few rays preserved are 

 moderately thick, the anterior ray being strengthened by several 

 imbricating and elongate fulcra. The caudal fin is deeply cleft and 

 equilobed, like the tail of the contemporary P. ornatus. There are 

 sixteen articulated rays, eight in each lobe, preceded by acutely 

 pointed fulcral scales, those on the upper lobe being the largest. 

 The scales on the Museum specimen are all more or less broken, but 

 the characteristic or principal series covering the flanks are well 

 preserved on Mr. Damon's specimen.' These form four rows of 

 high and narrow scales which gradually diminish in height as they 

 approach the tail, and are completed by smaller scales above and 

 below. The upper or dorsal row of large scales are slightly curved, 

 the anterior series of the other rows are nearly rectilinear in form. 

 Those of the second, or lateral line series of scales are the largest, 

 being four times as high as they are broad, whilst in the next series 

 these proportions are as three to one. There are from 32 to 34: 

 scales in each longitudinal row. The lateral line is prominent and 

 continuous, with a slight curve, from the operculum to the caudal 

 fin. The side scales show the peg and notch articulation, and are 

 strengthened on the inner surface by the continuation of the peg as 

 a mesial vertical ridge to the articulating depression on the lower 

 margin of the scale. The scales are coated with shiny ganoine, upon 

 which may be seen with a lens a few strige, or lines of growth, and, 

 compared with most species of PJiolidophorus, the scales are relatively 

 thin, hence their imperfect preservation. The specimens are from the 

 Lower Purbeck Beds of the Isle of Portland. 



Pholidophorus brevis, sp. nov. (Plate X. Fig. 1.) 



The little fish I have thus designated is in the National Collection 

 (P. 1074), and is readily distinguished from the preceding species 



* See Plate X. Fig. 3. The entire fish has been drawn (but not yet published), for a 

 new edition of the Supplement to the Geology of Weymouth and the Isle of Portland. 



