Gatty Marine Laboratory ^ St. Andrews. 253 



From the observations of Mr. Anderson Smith *, who kept 

 the adults of L. DecandoUi in confinement till they deposited 

 epgs, w'liich they did all at once, it appears that they hatch on 

 the twenty-eighth day. The circulation was noticed on the 

 thirteenth day. Mr. Holt correctly states that the embryos 

 are always horizontal in position ; indeed, the shape of the 

 egg would render any other position difiicult. In this con- 

 nexion it has also to be remembered that in the later stages 

 the embryos make considerable movements in the eggs. 



Mr. Holt found different degrees of development in the eggs 

 of those he examined, and slight variations were also observed 

 in those above-mentioned. The majority, however, in a 

 given case were nearly alike in this respect. The examina- 

 tion of the ovaries of an example of Lepadogaster DecandoUi 

 captured in a hollow tangle at Guernsey shows that the mature 

 eggs are accompanied by others of various sizes, the larger 

 about half the size of the mature. This species may differ in 

 some respects from the biraaculated sucker in regard to 

 spawning. Black pigment is well developed before hatching. 

 From the careful description of the larva, which measures 

 from 2'8 to 2*9 millim. on hatching, given by Mr. Holt, the 

 only difference in those examined (but whether L. bimacu- 

 latus or L. DecandoUi is an open question, since the females 

 of both species occurred inside this remarkable hatching- 

 chamber) is the presence of scattered black chroraatophores 

 over tlie dorsum of the head. The somewhat regular rows of 

 black specks along the sides of the body are characteristic 

 even at this early period. 



The young of the bimaculated sucker appear in the bottom- 

 nets as post-larval forms in August and September, and they 

 range from 5 to 5'5 millim. They probably remain, on 

 emergence from the capsule, more or less in the shelter of 

 their original home until the yolk-sac is absorbed and suffi- 

 cient strength is gained for a free existence and the capture of 

 prey. At this stage the larval tail is still present superiorly, 

 with its embryonic rays, wliile nine true rays occur beneath. 

 The minute black specks appear on the top of the head and 

 under the jaw, with a few on the abdomen, besides the rows 

 along the sides. The prominence of the alimentary canal 

 interiorly, with the vent posteriorly, is a feature at this stage. 

 A disk-like thickening occurs on the site of the sucker, but 

 the apparatus is little developed ; yet even the indication of 

 it is comparatively early, since the pelvic fins are generally 

 late in appearing. 



• Proc. Roy. Phys. Soc. Edinb. ix. p. 143, pi. vii. (1886j. 



