276 MR. GOSSE ON PEACHIA HASTATA. 



The nearest alliance of Anthea is with Actinia ; to which, in the texture of its skin, 

 and the absence of warts, pores and glands, it presents a close resemblance. The 

 received notion, that Anthea is incapable of entire retraction, I have elsewhere stated to be 

 incorrect ; and I have since had several opportunities of seeing it with the tentacles quite 

 concealed, and the animal assuming the ordinary butter-like shape of an Actinia. A 

 better character is the tendency which the tentacles have to form groups, like several 

 trunks of a tree united close to the ground. In this respect there is perhaps an approxi- 

 mation to Imcernaria ; remote, however, for the clusters thus formed are still in con- 

 tiguity with each other ; and the peculiarity cannot be discerned, except when the animal 

 is in the state of widest expansion. 



Finally, the species viduata appears to be the point at which the genus Sagartia leads 

 off towards the Echinodermata. Though, in an Aquarium, it remains attached for 

 months together, yet, in freedom, its adhesion is evidently very slight. It comes on shore 

 by hundreds, after a gale, on the Devonshire coast ; and is frequently dredged on sandy 

 mud, sometimes adhering to a small bivalve-shell, but more commonly free, with the 

 posterior extremity contracted, so as to resemble a thick pedicel. It burrows in sand ; 

 and, in conformity with such a habit, it has the power of great elongation. A specimen 

 which I have kept for the last six months, sometimes forms a slender column 5 inches in 

 height. From this vermiform creature the transition is so brief to the free IlyantMs, 

 that we hardly need to seek a place for mtestinalis and vermicularis ; and from Ilyanthus 

 to the genera Peachia and Edwardsia, of which I have spoken in the former part of this 

 Memoir, and thence to the Siptmculidce, the road is patent. 



These relations I have attempted to display by a diagram ; though I need scarcely say, 

 that such a representation cannot adequately express the varied consanguinities and 

 cross-alliances of the grand plan of Nature. 



EXPLANATION OF THE PLATES. 

 Tab. XXVIII. 



Fig. 1 . Peachia hastata : natural size. 



Fig. 2. The oval disk and tentacles; (a) the papillae of the oviduct : (magn. 2 diameters). 



Fig. 3. A tentacle (magn. 2 diameters). 



Fig. 4. The disk, with the papillae («) projecting: (2 diameters). 



Fig. 5. The mouth of another specimen, showing the orifice of the oviduct : (4 diameters). 



Fig. 6. A portion of the ovaries, with the convoluted bands : (10 diameters). 



Fig. 7- Thread-cell of Sagartia venusla, with the barbed thread emitted. 



Fig. 8. Thread-cell of the same, before emission. 



Fig. 9. The same, with the unbarbed thread. 



Fig. 10. Thread-cell and thread of S. Bellis. 



Fig. 1 1 . Thread-cell and thread of S. Troglodytes. 



N.B. All the thread- cells are magnified 560 diameters. 



Tab. XXIX. 

 The Diagram above referred to. 



