APPENDIXE: HEINCKE _ 16 — 



never in great quantities. Of the larvse, some were often far on in development (stage 

 when the fin-rays were forming) , so that from this also, it may be supposed that the 

 height of the spawning period was already over. 



On the May cruises, plaice eggs were no longer met with in the North Sea, here and 

 there, however, larvae and several times older stages, but never in any quantity. In the 

 hauls made in the open North Sea, on the Dogger Bank and Great Fisher Bank, these 

 larvse were obtained only very rarely \ e. g. once on the northern part of the Great Fisher 

 Bank and on the western edge of this bank (German Station IV); more frequently, though 

 still on the whole rarely, on the stations near the coast within the 40 m. line, in the 

 north near to the Jutland coast and in the south in the German Bight. 



The small number of plaice larvse, also of the younger plaice (without fin-rays) met 

 with in May, leads one to suppose that the largest quantity of these had already taken up 

 the bottom habitat. 



Amongst the numerous young flat-fishes in the latest planktonic stage, which were 

 taken in -July, the plaice never occurred in the open North Sea. 



The planktonic plaice larvse, according to our observations in the North Sea, reach a 

 length up to 17 mm., yet, as a rule the metamorphosis to the adult form and the pelagic 

 life, are ended at 14 to 15 mm. in length. 



The youngest bottom-stages and the 0-group. The smallest completed 

 bottom-stage of the plaice observed by us (incomplete stages i. e. still in the process of 

 metamorphosis, were never found on the bottom), measured about 13-5 mm. in length. We 

 have taken these earliest bottom-stages, and the somewhat larger stages to 50 mm. in length, 

 from the beginning of June to the end of August, and with but isolated ex(!eptions only 

 within the 20 m. line in the immediate neighbourhood of the land, mostly on sandy ground, 

 more rarely on muddy ground. We have hitherto obtained the youngest stages from 14 

 to 25 mm. in length, always and only when we fished with suitable small-meshed hand-nets 

 and shove-nets quite close to the shore in — 3m. in depth, thus within the tidal region; 

 for example, at the base of the rocks and on the sandy island at Heligoland. At the latter 

 place we take them, for example, in June, often in quantities in the so-called "Seyen", that 

 is, the small, shallow pools left on the beach of the island at ebb-tide, in whose loose sand 

 warmed by the summer sun the small plaice like to revel. The somewhat older bottom- 

 stages of the 0-group (from 25 to 50 mm. in length) were mostly found at the same 

 spot, but also in smaller numbers further out, 2 to 4 nautical miles from land, on 

 somewhat deeper ground, 10 even 20 m. in depth. On the g'*» and 10*'^ of July 1903, we 

 caught 2 small plaice of about 30 to 40 mm. in length, with the Heligoland trawl on sandy 

 ground in 16 and 25 m. depth, the one 20 sea miles W. from Amrum, the other about 

 25 sea-miles from land at Vyl light-ship. ■ 



In the open North Sea, we have only once taken a small plaice of the 0-group 

 in our numerous hauls with the Heligoland trawl and the shrimp trawl, which otherwise 

 brought up many thousands of smaU young fish, especially many young flat-fish of the 

 species Limanda and Drepunopsetta. This specimen was 48 mm. long and was taken on 

 the South-west Patch of the Dogger Bank, where we fished on fine sandy ground within 

 19 to 32 m. Its otoliths showed no white ring round the kernel. It would be of the 



' The détermination of these larvae with certainty, and especially their separation from the dab 

 {Pleur, limanda), leaves much to be desired on defective preservation. 



