ZYG^NA MALLEUS. 85 



describe it as extremely fierce and strong, often breaking tlieir hooks or 

 lines. It is taken about a league off shore, in from sixty to one hundred 

 fathoms water. 



There are four or five more species of this genus known to ichthyologists, 

 which are all characterised by the form and width of their heads compared 

 with their length. Mr. Yarrell, in his Supplement to the British Fishes, 

 (Part II. p. 65,) has furnished the naturalist with a valuable series of 

 sketches illustrating these forms. One of the most singular of these is a 

 new species (Z. laticeps, Cant.) recently discovered in the Eastern seas by 

 Dr. Cantor. In this, the head in width equals one half the length of the 

 whole fish, and appears to be five or six times as broad as long. In 

 Z. tudes, Val. (le Squale Pantouflier, Lacep.), which comes the nearest 

 to Z. malleus, the head is more convex in front, and comparatively much 

 less produced side-ways in proportion to its length ; measuring, in a straight 

 line from eye to eye, only twice instead of three or four times its length 

 (capita so. duplo latiore quam longo). Having been occasionally taken 

 in the Mediterranean,* this South American as well as Eastern species 

 may perhaps be met with also in Madeira by some future naturalist ; in 

 which case it may be recognised by attention to this point. *[• Of the re- 

 maining species, Z. Tiburo, Val. {Squalus Tiburo, L. Will. t. B 9, f. 3), 

 and Z. Blochii, Val. Bloeh. t. 117, have the nostrils remote from the 

 eyes, and the head vastly more convex in front ; whilst in the former 

 Brazilian species, it is also still less produced transversely, in proportion to 

 its length, than in Z. tudes, Val. ; and, in the latter, the side lobes are 

 remarkably recurved. Z. Mokarran, Rupp. on the other hand, is said to 

 have the fore-margin of the head nearly straight or rectilinear, and not con- 

 vex before the eyes. 



The following description is derived principally from two small female 

 individuals of Z. malleus, which measured about two feet in length. 



Shape of the body slender, elongate, more ventricose than usual in most Sharks 

 just behind the pectoral or behind the first dorsal fins, and attenuated forwards into 

 a sort of neck, as weW as backw^ards towards the root of the caudal fin ; this character, 

 however, has been exaggerated in the greater number of the published figures. 



Head transversely oblong, much depressed and flattened, set on the body rather 

 like the head of a pick-axe on its handle, than of a hammer, which is at right 

 angles with it ; the two side lobes turning slightly backwards, and the front edge, 

 which is thin, being convex, like the segment of a circle, and faintly waved 

 or festooned : its middle lobe is broadest and most prominent, very obtuse or even 

 slightly retuse in the middle ; and on each side can just be traced a smaller lobe, 

 between it and the nostrils, which are seated in a shallow sinus close before or 

 rather within the extreme and somewhat prominent angles of the front margin. 

 Just beyond these angles, on the outer margin, are the large and prominent pro- 



* Risso Hist. iii. 126. 



+ It should, however, be observed, that MM. MUller and Henle throw doubts on its distinctnesa 

 as a species from Z. malleus. 



VOL. r. H 



