DEVELOPMENT AND LIFE-HISTORIES OF TELEOSTEAN FISHES. 855 



About a fortnight later, viz., on the 14th April, young Clupeoids (stage D) were 

 procured off the Pier Rocks by the mid-water net at 4 fathoms, along with a few young- 

 sand-eels, which are distinguished in spirit by their greater opacity and the larger pigment- 

 spots forming an interrupted ventral line, as well as by the more or less median position 

 of the anus. They are now from 12 to 15 mm. in length, and show the interrupted line of 

 black pigment-spots from the pectorals to the middle of the body, after which the spots 

 are so closely approximated that they seem to form one line to the anus, which has a 

 speck or two externally on each side. These pigment-touches are all elongated antero- 

 posteriorly, those behind the middle being linear. A few specks also appear on the 

 ventral part of the caudal, next the notochord, and sometimes above the latter in those 

 most advanced. The somewhat thick notochord passes straight backward, and the 

 general outline remains spathulate. The embryonic fin-rays are still present, but the 

 ventral region of the tail shows considerable opacity from the development of the 

 hypural elements. A delicate narrow marginal fin is continued forward from the tail to 

 the vent, and from the front of the latter a thin border runs ventrally almost to the 

 pectoral region. Dorsally in the region of the process formerly noticed (i.e., above a 

 vertical line in front of the anus), a permanent dorsal fin is developing, its posterior 

 border being somewhat abruptly sloped, while its anterior runs into a thin marginal fin 

 which proceeds some distance forward. The base of this fin is opaque. The upper jaw 

 has increased in length, but the mandible is only slightly longer. The mouth forms a 

 large transverse slit. The brain and spinal cord are clearly seen anteriorly, and the 

 otocysts are still large. The branchiae communicate freely with the water. 



At this stage the fishes are probably not less than a month old. 



On the 28th April (two weeks subsequently) most have reached the length of 16 mm. 

 (stage E), and the depth of the body has notably increased. The dorsal fin is larger, and 

 so is the caudal, while the ventral opacity in the latter is also greater. The ventral and 

 caudal pigment is more distinct, and most specimens present a median streak of pigment 

 in front of the pectorals. The opercular fold is now growing over the branchiae, which 

 do not yet show papillae. Viewed from above, the snout is broadly spathulate ; and the 

 alimentary canal is generally empty. Four days later all the structural features just 

 mentioned were better marked, and the notochord showed a tendency to bend upward 

 at the tip, but there was no increase in length. 



A notable enlargement was observed on the 16th May (stage F), the length being 

 now 20 mm., and the depth in the median region of the body was much greater, the part 

 immediately behind the pectorals having, however, a less depth than the succeeding, but 

 it was thicker transversely, so that there was less abruptness between the head and the 

 body. The pigment- touches along the ventral edge are much larger, still, however, 

 preserving their elongated shape and disposition — that is, arranged as an anterior series 

 of larger and a posterior of smaller specks terminating at the anus. The latter is 

 situated at this stage about the commencement of the posterior seventh of the body. 

 The snout retains its spathulate outline, the pectorals are large, and the dorsal shows 



