THE society's NOTE-BOOKS. 243 



of residence, namely, attached to the shells of oysters, and al- 

 though the dependence in this case is purely a mechanical one, 

 this is a first step towards parasitism. 



But the Sea-Fir has an additional interest attached to it beside 

 that of parasitism, both from its structure and development. The 

 casual wanderer along the sea-shore, picking up a branch of this 

 zoophyte, would at once place it among the sea-weeds, and 

 would look very doubtfully upon the naturalist who informed him 

 of its real nature, so plant-like is it in its manner of growth. 



On reference to PI. 43, Fig. 13 (which gives a fair illustration 

 of its general appearance), it will be seen to consist of stem and 

 branches; upon the branches (Figs. 10, 11, 12) are borne little 

 cups, each containing a hydra-like animal. A section of the stem 

 and branches (Fig. i) shows that both are hollow, and in free 

 communication with the cups. 



Plate 43, Fig. i, gives a diagrammatic section of Sea-Fir, 

 showing its structure. Outside is a horny covering (c.c), which 

 supports the entire organism, and which expands to form the cups 

 (d.d.), in which the little animals reside. Each animal possesses a 

 mouth (;;/.), surmounted by tentacles (/./.), the mouth leading to a 

 simple body-cavity (l^.c), in direct communication with the stem 

 {a.a.}. The layers consist of an Ectoderm (tr.) and Endoderm 

 (en.) ; the arrows show the communication. 



Through this channel each polype ministers to the general 

 nutrition of the colony, and draws its own food-supply from the 

 common fund thus formed. 



Development. — From certain receptacles (Figs. 2, 3, 4), 

 which are developed upon the branches, true eggs (Fig. 5) 

 are discharged into the water. Each egg at first swims 

 freely in the water, but afterwards settles down (Fig. 6), and 

 prepares to fulfil its function as founder of a new colony, and as a 

 first step throws out a bud (Fig. 7), which becomes a single ani- 

 mal (Fig. 8), and as soon as this is fairly started in life it begins to 

 bud. These buds remain attached (Fig. 9), and in turn produce 

 other buds, thus developing the plant-like form of the polype. 

 For the illustrations on the development and structure, and for 

 much of the matter in the above Notes, I am indebted to ^^Sdmce 

 for All,'' Vol. II. 



J. W. Measures. 



Holotlmria.— This word, literally translated from the Greek, 

 means " all-doory," so that the Greek and English equivalents are 

 remarkably similar, and the German word would be " all-thiirig." 

 I should therefore suppose (for I do not know the animal), that it 



