58 LIFE BY THE SEASHORE. 



only bear zooid-cups (a), a single one to each. Above each 

 cup are two minute cup-shaped nematopliores (/), while 

 beneath each is a single one (b"). The short joints also bear 

 a single nematophore, but no zooid-cup. Other nematophores 

 occur at the joint of origin of the pinna3, and on the main 

 stem (b" r ). The gonothecaB (c) arise at the angle between 

 pinnaB and stem, and are remarkable for their long tubular 

 necks. 



The Calyptoblastea are so abundant on the shore that 

 even at the risk of wearying the reader, we may briefly 

 review the different families. Sea-firs which bear distinct 

 bells borne on stalks belong to the Campanularians, which 

 have large zooids, and vary much in their branching. 

 Where stalked cups occur which are not bell-shaped, but 

 ovate and conical, the colony must be referred to the 

 Campanulinidse ; but if the cups are numerous, tubular, 

 and without a stalk, then the specimens belong to the 

 LafoeidaB. In the " herring-bone coral " the cups are similar 

 and also without a stalk, but they are arranged in two rows 

 at the sides of the flattened stem. In the Sertularians the 

 deeply sunk cups, the jointed stems, and the arrangement 

 of the cups make the colonies resemble some firs, or the 

 backbone of a little fish. Finally, the Plumularians are like 

 little feathers, and have their cups placed at one side of the 

 stem only. 



From this survey of the littoral Hydrozoa we may gather 

 a general idea of the special peculiarities of these curious 

 and beautiful animals. All the forms we have considered 

 are colonial, living in communities often formed of an enor- 

 mous number of individuals, which are mutually dependent, 

 and are connected by a ramifying series of canals. In 

 the next group of Coelentera the sea-anemones and their 

 allies this colonial habit is less common in our seas, though 

 even there colonies quite analogous to those of the sea-firs 

 do occur. Again, except in Hydmctinia, we have found 

 that the individuals of the colonies show little division of 

 labour; we have nutritive persons, or hydroid polypes, and 

 reproductive persons, sporosacs or swimming-bells, but with 

 the exception already made, the hydroid members of any 

 colony are all similar. Now in certain free-living Hydrozoa, 

 which are abundant in warm seas, but very inadequately 



