DEVELOPMENT AND LIFE-HISTORIES OF TELEOSTEAN FISHES. 811 



nent. The head is large, and the body shows an evident increase in size. The first and 

 second dorsal fins are still continuous, though their separation is indicated by an indenta- 

 tion. Embryonic fin-rays alone are present, those of the anterior moiety or first dorsal 

 being short, while the longest rays occur about the posterior third of the second dorsal. 

 This is a marked feature when contrasted with the adult, the anterior rays of whose first 

 dorsal fin far exceed the others in length and strength. The caudal fin is more distinctly 

 separated from the dorsal above and the anal below. Dorsally the marginal fin at the 

 base of the caudal almost ceases behind the second dorsal, but ventrally it is broader 

 and less distinctly separable from the anal. It still exhibits merely embryonic fin-rays. 

 The caudal fin is somewhat conical in shape, being broad at the base and sloping 

 to the projecting median rays, and thus very different from the slightly emarginate 

 adult fin. 



The hypurals form an almost vertical border from edge to edge, i.e., dorso- ventrally, 

 and the notochord now barely projects from the superior angle. Above the latter several 

 linear (opaque) tracts indicate the superior accessory fin-rays, and inferiorly shorter rays 

 appear next the hypurals. The anal fin shows fin-rays similar to those in the dorsal 

 fin. The pectorals are still of large size, the upper rays being about double the length of 

 the lower. The three lowermost rays that ultimately become free filaments are webbed to 

 the tip. Black pigment has greatly increased over the fin, especially distally, and a black 

 margin passes a considerable distance posteriorly. The ventrals now extend slightly 

 beyond the anus. Black pigment-corpuscles have increased over the head, cheeks, 

 abdomen, and ventral line of the body. 



Frequently in this and the earlier stages specimens of a Crustacean (resembling the 

 young of Caligus) are found fixed to the head or other regions by the long central 

 process. 



When the gurnard attains a length of 17 mm., the caudal fin is separate from the 

 second dorsal, and has several accessory fin-rays. It is also free inferiorly, but the 

 separation is marked by a gap behind which a portion of the marginal fin runs on to join 

 the caudal, where the accessory fin-rays begin. The most prominent part of the caudal 

 fin is still the median border ; but the complete separation of the anal and dorsal fins, 

 and the growth of the superior and inferior fin-rays, produce a great change in its 

 appearance. The first dorsal is not quite wholly separated from the second, and its rays 

 are considerably longer than in the foregoing stages, while the posterior rays of both 

 second dorsal and anal are longer than the remaining rays in these fins. Black pigment 

 is scattered over the entire surface of the pectoral fins, extending, indeed, as far forward 

 as the border of the branchiostegal region. The lengthening of the body beyond the tips 

 of the pectoral fins causes the latter to appear somewhat shorter. No separation of the 

 three anterior filaments of these fins has yet occurred. The ventrals have grown slightly, 

 and extend a little further beyond the anus. The branchiae are now much more definitely 

 pinnate than hitherto, and resemble the barbs of a growing feather. 



At the next stage demanding special notice, the young fish measures about 21 mm. 



