24 



INVERTEBKATK ANIMALS. 



gillum, not larger than a Laburnum seed, may 

 be seen on the tube. 



Upper Compartment. 



The tube of Kuphus g'lganteus. Specimens of wood 

 perforated by Teredo, often called the Ship- 

 worm, shewing the destructive character of the 

 borings made by this animal. 



The Mark ^ indicates specimens or otlier illustrations exhibited in the Cases. 



Group 73.— Class PTEROPODA. Trxjpov, a wing; rnvg. 

 a foot. Pelagic Mollusca, of small size, often found 

 swimming in countless myriads on the surface of the 

 deep, especially on calm evenings, from the tropics to 

 high latitudes. The shells are delicate and glassy. 

 The animals are very simply organised, and resemble 

 the minute but actively locomotive larvae of the sea- 

 snails. Estimated number of species : recent, 73 ; 

 British seas, 5 ; fossil, several species of Conularia, and 

 other genera, from the Silurian upwards. 



IT Examples of about 40 species of Balant'mm, 

 Cavolina Hyalcea, Clio, Limacina, and 

 other genera. 



Series containing more than a few species of 

 Pteropoda are rare in collections. For the 

 comparatively numerous examples here exhi- 

 bited, the collection is indebted chiefly to 

 Captains of merchant vessels sailing from 

 Liverpool, especially to Captains Whiteway, 

 Mortimer and Baker. 



