60 



of the common Cottus will be seen in these lists, yet ouly a purt of the O group 

 which is still pelagic in the beginning of May, as the bottom-stages, which must 

 already be present in tliis month, were not taken by these iuvestigations. The 

 I gronp of the common Cottus is from 3 to S'/t inchés (ca. 8 — 13.5 cm.). The males 

 are a little smaller than the females. This difference in size becomes even more 

 distinct in the II group, which includes females from 6 to 9^4 inches (ca. 15.5—25.5 

 cm.) and males from 5'/^ to 87^ inches (ca. 14 — 21.5 cm.). None of the I group 

 have yet spawned, whereas the II group is composed of spawned speciraens. The 

 common Cottus tims attains maturitii at the end of its second ijear. 



There are likerwise three groups of the long-spined Cottus in the lists. The 

 smallest specimens, of IV4 to 3V2 inches (ca. 3,5—9 cm.) are about a year old 

 and, as the pelagic young do not occur in the beginning of May, must be ascribed 

 to the O group. Above this group, the list for the females sliows two groups almost 

 fused together. The I group is about to conclude its regular growth and join on 

 to the older years in a common group, which ou the appearance of the new 

 O group (i. e. the pelagic young) would be cailed the II group. The list for the 

 males of the long-spined Cottus is rather irregular, but the conditiou is certainly 

 the same as for the females, viz. that the I grup is about to fuse with the II group. 

 The males ai'e sraaller than the females. All the specimens of the I and II group 

 are taking part in the spawuing. The long-spined Cottus, like the common Cottus, 

 in thus mature at the end of its second gear. 



It appears from the lists of measurements, that the growth of the common 

 Cottus at Fænø is more rapid than that of the long-spined species; but the growth 

 in other parts of the Danish waters is perhaps not the same as that observed 

 at Fænø. 



Resumé. The common Cottus spawns in December — January. The pelagic 

 young are very abundant in the inner Danish waters in January — April (May, 

 June). The bottom-stages have been seldom found. 3Iaturity begins at the end of 

 the second year, when the ordinary groivfh ceases. 



The long-spined Cottus spawns in April — May. The pelagic young appear 

 in May — June; they are much more rare than the pelagic young of the common 

 Cottus. The hottom stages have seldom been found. Maturity begins at the end of 

 the second year, when the ordinary growth ceases. 



Pogge, Agmtus catapJiradus. 



Just as for the two Cottus species we have also good information regarding 

 the spuwning time of the pogge from the spring of 1902, when iuvestigations were 

 carried on in the Little Belt by the Biologicai Station. 



I). 10— 3 — 02. Off Fredericia. English trawl; 1 Agonus with large, light red, almost 

 ripe spawn. 



D. 22—3—02. Fæno Sound. One Agonus witii spawn talfen in cod traps. 



D. 7 — 4 — 02. An Agonus lias laid soine dumps of spawn in "Stationens'' tank, wliere 

 it lias lieen for a few weeks. 



The eggs laid in the tank on April 7th have been described by Johs. 



