SEAWEEDS. 139 



fronds beings tubular instead of flat. The clusters of 

 spore cases are mixed with filaments, hence the name, 

 which means rough seed. The Compressed Asperococcus 

 is occasionally thrown upon the coast of Devon. Turner's 

 Asperococcus is found on stones on muddy shores, and 

 the Prickly species is also native to the Devonshire rocks. 



The order of Chordariacese contains but a few humble 

 weeds, some parasitical, some mere incrustations. We 

 found one of the most important members of the order, 

 the Chordaria Flagelliformis (Plate II., Jig. 5), growing 

 on stones on the shore at Oban ; it resembles the Dic- 

 tyosiphon Fceniculaccus, when its fibres are worn off. 

 The Chordaria Divaricata has very irregularly divided 

 branches, sometimes tAvo feet long ; it lives in deep 

 water. 



The Mesogloias have also much divided thread-shaped 

 fronds ; M. vermicularis is pretty frequent on our shoi 

 in summer, the branches are thicker in proportion to 

 their length than in the allied weeds, and are slimy to 

 the touch. 



The Leathesia tuberif oralis we did not find till after- 

 wards, like an empty grape skin ; it was lying among 

 rocks at Arran ; its globular form makes a strong contrast 

 with its allies. It is named after Mr. Leathes, a dis- 

 tinguished naturalist. 



The Ealfsia is a mere incrustation, a marine lichen, 

 named after Ealfs, the botanist, dark brown in colour, 

 and tough in texture. 



A quantity of coarse olive weed, which we drew from 

 the sea at low water, furnished us with specimens of the 

 minute Elachisteas. The fronds in this family consist 



