Mr. J. Y. Johnson on new Fishes from Madeira. rie 
‘scales. Abdomen prominent and keeled. Mouth large, non-pro- 
tractile ; minute pointed teeth in the jaws, none on the palate ; a pair 
of large tooth-like bony processes projecting from the anterior ends 
of the maxillaries, and entering the mouth between the vomer and 
the premaxillaries. Head, opercular pieces, and mandibular bones 
bearing numerous thin bony crests. Eyes large. A single dorsal 
fin commencing about the middle of the body over against the anal 
fin, both being continuous. Perfect thoracic ventral fins, with a free 
bony appendage at the upper angle of their roots. Pseudobranchia 
present. Branchiostegal membrane with seven rays. No lateral line. 
The small but highly interesting fish upon which this new genus 
has been established appears to be allied to fishes belonging to genera 
some of which have been placed by Dr. Giinther amongst the Scom- 
bride, others amongst the Carangide—families distinguished by him 
on account of differences in the number of the vertebre. I have 
been unwilling to open the single specimen obtained with a view to 
the determination of this point, but place the genus provisionally 
amongst the Carangide on account of its many resemblances to dn- 
tigonia. It may be entered in the synopsis of the genera of that 
family (Cat. Brit. Mus. Coll. p. 418), in sect. 6 of the first group, 
Carangina, thus :— 
Ventrals with a free bony appendage. 
These appendages, the tooth-like processes of the maxillaries, and 
the crests about the head present an assemblage of characters quite 
sufficient to separate this form distinctly from all other known 
Acanthopterygian genera, 
DIRETMUS ARGENTEUS, Sp. n. 
Re eiNcaes Fs lbe, Va10? C. 19. M.B.7,. 
The body is much compressed, and so elevated that without the 
tail and its fin it is subcircular. The height to the total length is 
about 1 to 12. The abdomen is prominent and keeled, and the nape 
is trenchant. It is of a silvery-grey colour, with darker grey near 
the dorsal and anal fins. The skin, when the scales are removed, 
is fuscous. The whole body is clothed with small, somewhat deci- 
duous scales, having four or five broad teeth at the edge and some 
minute spines on the exposed surface. ach scale is constricted at 
the middle ; the posterior portion is rather larger than the anterior, 
and marked with curved transverse striee. The head is large, being 
contained in the total length only about 22 times. It is remarkable 
for the numerous crests of thin bone, many of which are minutely 
denticulated. The cheeks are scaly ; but the opercle and maxillary 
are without scales. The eye is round and large, its diameter com- 
pared with the length of the head being as 1 to 21. It is placed 
high up, a diameter and a half above the throat, but does not quite 
reach to the profile, and a space equal to less than half the diameter” 
intervenes between it and the muzzle. A thin bony crest is placed 
behind it, and another in front of it, the latter forming a funnel- 
shaped cavity below the rather large nostril. Between the eyes there 
are three low crests without serratures, the middle one of which di- 
