264 Dr. R. 11. TriUjuair on Fossil Fishes 



in impression on the half of the nodule represented in fig. 1. 

 In the diagrammatic outline, fig. 2, the second supraclavicular 

 is seen largely covered by the somewhat disjdaccd ()|)crculum. 

 Both supraclaviculars agree very closely in form and position 

 with the corresponding bones in Mcsolepisj as seen by coui- 

 ])arison with a very beautiful and ])crfcct specinuMi of J/, sat- 

 laris, Young, kindly lent me by my friend ^Ir. A\'ard. Some 

 traces of an elongated clavicle are also seen, but not suf- 

 ficiently marked for description. 



Fins. — The specimen shows no trace of either pectorals or 

 venti;als. The dorsal fin is small, and connnences consider- 

 ably behind the centre of the arcli of the back ; it is composed 

 of immerous closely set rays, divided by very frc(pient trans- 

 verse articulations. The most anterior rays are very short, 

 but they increase rapidly in length to the ninth or tenth, from 

 which the margin of the fin again falls away, so that it becomes 

 more fringe-like posteriorly, Avhere the rays are seen also re- 

 peatedly to bifurcate. Traces of fine fulcra arc seen on the 

 anterior margin. On the opposite aspect of the body some re- 

 mains of the anal fin are seen — unfortunately only a few broken 

 rays ; yet from these we may pretty safely conclude that it cor- 

 responded in size and position to the dorsal. 



Scales. — The scales of the side of the body are high and 

 naiTOw, diminishing very regularly in size from before back- 

 wards. Their form is rhomboidal, the acute angles being the 

 posterior-superior and the anterior-inferior. The external 

 surface of each presents a well-defined, smooth anterior 

 margin, produced downwards into the lower acute angle or 

 point of the scale, overlapped by the scale in front, and corre- 

 sponding to the thickened articular rib on the internal aspect. 

 The latter is by no means strongly marked : it passes above 

 into a pointed articular spine of moderate size ; and below, it 

 is obli(|uely bevelled off behind for the articular depression 

 which receives the corresponding peg of the scale next below. 

 The exposed suiface is ornamented by a beautiful granular 

 tuberculation, the little tubercles sometimes being arranged in 

 lines or coalescing into short ridges, whose direction is always 

 more or less across the scale, some tendency to radiation 

 downwards towards the posterior-inferior angle being also 

 often observed towards the lower part. This tendency of the 

 tubercles to coalesce into transverse ridges is most pronounced 

 in those scales which are situated more posteriorly (PI. XVI. 

 fig. 3), though I observe it also in one placed just behind 

 the lower part of the suboperculum. The two scales repre- 

 sented in fig. 3 are from the lateral line, a little in front ot the 

 origin of the dorsal fin ; they are seen to be each marked with 



