DEVELOPMENT AND LIFE-HISTORIES OF TELEOSTEAN FISHES. 865 



last stage, and a pale process or papilla indicates the presence of the ventral fins. The 

 next stage to be noticed (about 5 mm. in length) shows a more regular fusiform outline, 

 and from the increase of pigment along the ventral surface it is considerably darker than 

 the dorsal. By the widening of the cheeks the eyes have become more oblique, so that 

 they are largely seen from the dorsum, whereas in the earlier stage they were more in har- 

 mony with the usual piscine type. The forward growth of the premaxillary region, and 

 the increased arch of the mandible, greatly alter the facial aspect. The ventrals appear 

 as a pair of short fins below and in front of the pectorals. From the marginal fin the 

 anal is differentiated inferiorly, and is separated by an interval from the caudal. The 

 fin-rays are much more distinct in this lower fin than in the dorsal. The development of 

 the hypurals has pushed the tip of the notochord upward, but it is still surrounded by 

 the embryonic marginal fin. The inferior caudal rays far exceed it in length, and they 

 spring from a vertical hypural edge. The shape of the tail is conical, broad at the base, 

 and narrow at the tip. The opercular margin does not yet show spines. 



When 1 or 2 mm. longer, the arrangement of the pigment is unaltered, the ventral 

 surface and posterior region of the body being tinted somewhat deeply by stellate 

 pigment-corpuscles, while the dorsum is less uniformly coloured. The body behind the 

 abdomen is thicker, so that when seen laterally the fish is fusiform, though, viewed from 

 the dorsum, the head and abdomen are still disproportionately broad. The pectorals and 

 ventrals are larger, the former showing blackish pigment-specks on the fleshy basal region, 

 and a few dark radii on the fan-shaped distal region. The under surface of the ventrals 

 also exhibits dark streaks between the rays, and they are considerably shorter than the 

 pectorals. In shape both pairs of fins approach those of the adult. The first dorsal is 

 merely indicated by a few short processes. The pale second dorsal fin (the embryonic 

 fin having disappeared) begins behind the middle of the back, and terminates a short dis- 

 tance in front of the caudal fin. From the anus the anal fin extends to a point below, and 

 somewhat beyond the dorsal above, as shown by an imaginary vertical line. Between 

 the rays very evident dark pigment-streaks occur, a feature in consonance with the 

 development of pigment on the ventral surface. The tip of the embryonic tail has now 

 coalesced with the upper lobe of the permanent caudal, and the latter is somewhat less 

 conical as well as broader at its termination. In some of the more advanced specimens 

 at this stage the opercular armature is present as a straight spine, with a spur — coming off 

 nearly at right angles — toward the tip. 



When the length of 9 mm. has been attained, the body is still stouter behind the 

 abdomen, the ventral fins have gained greatly on the pectorals, so that though they arise 

 considerably in front of them, their tips are nearly in a line with the extremities of the 

 former. The fan-like pectorals have much stiffer rays, arising from the semicircular 

 base. The opercular spines stand out on a long process, and their tips slightly incline 

 towards each other, the margin between them being semicircular. The first dorsal is now 

 distinct, and the anterior rays of the second dorsal are longer than the others. 



When 10 mm. long, the characters of the adult are more evident, the telescopic mouth 



VOL. XXXV. PART III. (NO. 19). 6 S 



