On the Invertehrate Fauna of the Balti 



herring Avitli the water are separated from it by this branchial 

 basket, and accumu- 

 lated at the back of 

 the buccal cavity so as 

 to be swallowed {see 

 woodcut). 



The branchial bas- 

 ket is constructed in 

 the sprat exactly as in 

 the herring. 



In most other fishes 

 which occur in abun- 

 dance in Kiel Bay, 

 such as Behne rostra- 

 taj Zoarces viciparus^ 

 AnguiUa Jluviatilis, 

 Platessa vulgaris^ P. 

 Jiesus, Gadus mor- 

 rhua^ Gasterosteus 

 aculeatus, and Gaste- 

 rosteus sjjinacJiia, the 

 teeth of the branchial 

 arches are shorter and 

 further apart than in 

 Clupea harengus and 

 C. sjirattus. These 

 fishes, therefore, can- 

 not be competitors for 

 food with the herrings 

 and sprats. And that 

 they are not so is Three teeth of the second branchial arch of the 

 proved by the contents right side, from a herring 23 centims. long. 

 of their stomachs Inside view from the cavity of the mouth, 

 which usually consists 

 of Mollusca and mo- 

 derate-sized Crustacea 

 ( Gammarus locusfa, 

 Mysis sjJviuIosa,Sind Palcemon squilla) or of small fishes, which 

 they must seek chiefly at the bottom. 



The mackerel {Scomber scombrus) alone is furnished with 

 a branchial basket almost as close as that of the herring. As 

 in the herring there are long teeth on their outer branchial 

 arches; in a small mackerel, 18 centims. long, the longest 

 were 8 millims. long, and 0*8 millim. from each other. At 

 the sides also these teeth are furnished with spines, which are 

 even longer and thinner than in the herring. The following 



and so that the hinder side of the teeth may 

 also be seen. The two rows of spines stand 

 at imequal distances from the inner margin 

 of the tooth, as shown by the annexed out- 

 line of a cross section of a tooth. 



