15 
two or three times as deep as l)road, while those situated dorsally and ventrally 
(PI. IV, Pii^. 3) are more nearly etjuilateral. The exposed area in all is 
somewhat rhomhoidal in shape — especially so in the dorsal and ventral scales; 
and the external ornament consists of numerous fine tuherciilations, with an 
occasional tendency to arrangement in lines concentric with the free 
borders. 
In the caudal region, behind the line already mentioned, the scales 
become immediately thin, decjily overlapping, and cycloidal. As shown by 
the line group of remains (No. c), there a})[)Gars to be some gradation from 
these scales to those of the abdominal region just described ; and the original 
of PI. IV, Pig. 5, is evidently to be regarded as one of the intermediate 
forms. Here the overlajipcd area occu])ies nearly half of the scale ; the 
upper peg is broad and short ; the concentric lines of growth are distinct, 
and the superficial tubcrculations more clearly follow these than in the 
majority of the scales of the abdominal region. Except near the dorsal and 
ventral borders, the cycloidal scales arc ovoid in shape, with tin; long axis 
vertical; and a typical specimen of the series traversed by the lateral line is 
shown in PI. IV, Eig. O. The exj)oscd area now forms only a deep sector 
extending backwards from the middle point ol‘ the scale ; and the anterior 
half Avas evidently overlapped by parts of two scales, one above and one 
below. There is a short, horizontal, raised line immediately behind the 
middle of the scale, probably indicating a perforation for the passage of the 
lateral sensory canal ; and the exposed sector is ornamented in the nsual 
manner by tuberculations following the lines of groAvth. An imperfect scale 
from the lower part ol‘ the caudal pedicle (PI. IV , Eig. 7) shows that in this 
region the scales are nearly as broad as deep ; and in the type it is quite clear 
that there was no postcro-superior production of the caudal region into a 
lobe. 
Eb;;z//y~PH0LID0PH0RID.a]. 
APtCIIJCOM.ENE, ffru. 
(ieu. Char . — Trunk fusiform and laterally compressed ; atrophied 
upper caudal lo])c conspicuous. Head small and snout obtuse ; one large 
suborbital occupying the greater part of the cheek behind the orbit ; oral 
border of maxilla convex ; teeth all small, those of the margin of the jaws 
arranged in close regular series. Notochord persistent ; hypocentra and 
pleuroccntra rudimentary or absent ; ribs long and slender. Ein-rays all 
