43 



Ihe gut is white, thin, and delicate, a little flexuosc, but 

 not convoluted, and it is twice the length of the stomach. 



Length, four inches. 



IIab. The exact localities where this fish was taken are 

 unknown ; but it is supposed to be, like the Myctophi, an 

 inhabitant generally of the warmer parts of both oceans. 



Hemiscyllium trispeculaue. Richardson. 



Plate XXVIII. 



Hemiscyllium trispeculare, Richardsou, Icones Piscium. Lond. 1843, 

 p. 5, Plale I., fig. 3. 



This species was first made known in the work above 

 quoted, wherein a coloured figure is given from a drawing 

 by Lieutenant Emery, of Her Majesty's ship Beagle, of a 

 specimen taken at Turtle Island, on the north-west coast 

 of Australia. A specimen, in perfect condition, obtained 

 by Benjamin Bynoe, Esq., Surgeon of the Royal Navy, 

 on the same coast, has entirely removed the doubts I en- 

 tertained of this fish being a variety of the previously 

 known species Hemiscyllium ocellatum. In general form 

 the two differ little ; but in trispeculare the pectoral, 

 dorsal and anal are somewhat more distant from the tip of 

 the snout, and more definite discrepances exist in the shape 

 of the scales, and the form and distribution of the spots 

 on the body. 



H. trispeculare has an obtuse snout, from whence the 

 profile rises in a convex cun'e, to blend with the dorsal 

 line opposite to the pectorals. It then descends a little 

 to the first dorsal, and runs straight from thence to the 

 caudal fin, whose upper border is slightly arched. The 

 ventral line is more nearly straight, the belly being only 

 moderately prominent. Between the pectorals and ven- 

 trals, where the body is thickest, the vertical and trans- 

 verse diameters are equal, and measure two inches in our 

 specimen. The belly is wider and flatter than the back, 

 and the fish tapers gi'adnally to the beginning of the anal 

 fin, at which place the height has diminished to one-third. 

 Behind the second dorsal, the compression of the tail be- 

 comes evident, and goes on increasing to the tip. 



On its upper surface the head is flatly rounded trans- 

 versely, varied by a slight prominence of the eyebrows. 

 From above the pectorals, to the first dorsal, the muscles, 

 swelling on the top of the back, produce a mesial furrow, 

 which is replaced by a low, rounded ridge between the 

 dorsals, the narrower top of the back there being flatfish. 

 The same form extends for a space behind the second 

 dorsal, but in the increased compression of the tail, at the 

 origin of the caudal fin, the flatness above is wholly lost, 

 and the blunt upper edge of the fin appears as a continua- 

 tion merely of the mesial ridge. The tip of the caudal is 

 rounded, with a minute notch at the point of the spine, 

 dividing it into two lobes, the lower of which is largest. 

 In our specimen of ocellatum, this small notch is wanting. 

 The belly is flattish below, and the swelling of the side 

 muscles between the claspers and anal forms a mesial 

 furrow. 



The spiracles, which are curved and rather oblique, have 

 the same relative position as in ocellatuui , and the folds 

 about the nostrils and mouth are also essentially the same 



as in that species. The inner nasal flap ends squarely on 

 the edge of the mouth, and is flanked exteriorly by a 

 thickish, tapering barbel, which originates at the anterior 

 end of the nasal furrow. A middle .space separates the 

 nasal flap of one nostril from that of the other, and the 

 outer border of each nostril swells into a thick roll, which 

 also reaches the orifice of the mouth, and is there sepa- 

 rated by a deep scalcless fissure from the large rolls at the 

 corner of the mouth, or, as they may be considered, the late- 

 ral lips. At first sight, the lower lip seems to consist of three 

 lobes, and the side lobes have actually free edges, and are 

 bounded by scaleless membranous fissures, but the middle 

 lobe is merely a pouting of the part continuous with the 

 scaly integument of the throat. The surfaces of all the 

 flaps or lips which have been mentioned are scaly, but the 

 fissures are smooth and membranous, and when the outer 

 lobes of the lower lip are raised, they seem to be retained 

 by a membranous bridle. 



The teeth are three-lobed, all the lobes being obtuse in 

 such teeth as have advanced to the edge of the jaw, but 

 the posterior and newer ones have the middle or hinder 

 lobe more elongated and pointed. In the upper jaw, be- 

 hind the dental plates, there is a thickish, plaited velum, 

 having a shaggy surface. In the lower jaw, a central 

 bridle runs to the tip of the tongue, dividing, in its course, 

 two concentric folds of membrane, looking like two rela, 

 and, when the tongue is raised, forming two cells on each 

 side of the bridle. 



The last three gill-openings are over the pectoral, and 

 the last two are nearer to one another than any other pair, 

 contrary to a remark of Miiller and Henle, that in this 

 genus the last two openings are not approximated. We 

 observe the same thing in our specimen of ocellatum. 



The skin has a peculiarly neat, smooth, shining, though 

 granular aspect, and feels rough only when the finger is 

 drawn towards the head. Figure 7 represents a scale of 

 trispeculare, and figure 8, one of ocellatum, showing their 

 difl"erence of form. 



Although there is a general resemblance in the bands 

 and distribution of the black patches on the fins of the 

 two species, the markings on the body differ very greatly. 

 In trispeculare, the spots, having a dark and rich brown 

 colour, are in clusters of three or four, united into a larger 

 spot by a lighter brown tint ; while in ocellatum they are 

 single, fewer, and more scattered. The black spot with 

 a pale border, behind the gill-opening, is oblong in ocel- 

 latum ; but in trispeculare it is perfectly round, and two 

 of the compound spots behind it being much darker than 

 the rest, form, as it were, two additional ocelli, but not so 

 perfect as the principal one. Much smaller spots thickly 

 cover the top and sides of the head of trispeculare, and 

 the ground-colour of the fish is represented in Lieutenant 

 Emery's drawing as yellow. The belly is spotless in both 

 species. As the figure gives the form and distriburion of 

 the spots and bands with much accuracy, it is unnecessary 

 to describe them at gi-cater length. 



On opening the belly, the liver is seen hiding the intes- 

 tines. A deep cleft divides it into two lobes, the right one, 

 ending in an acute lanceolate tip, being the longest. The 

 left lobe is broader, and from beneath its obliquely trun- 

 cated end, the fundus of the stomach appears, having the 



G 2 



