376 ACIIARADRIA LARYNX. 



Indeed, the hydranths of Acharadria and Halocordyle with their verticils of filiform and capitate 

 tentacles present no difference of generic value, and in the absence of all knowledge of the 

 gonosome in Acharadria, we can find nothing but the symmetrical ramification of Halocordyle to 

 contrast with the simple or irregularly i-amified hydrocaulus of Acharadria as grounds of generic 

 distinction. The whole habit of Acharadria, however, is widely different from that of Halo- 

 cordyle, and it is probable that if the gonosome of Acharadria were known, it would be found 

 to differ no less than the trophosome does from that of Halocordyle. It is possible, however, 

 that Acharadria is but the immature state of some already described form of pennaridan 

 hydroids. 



AciiAKADRiA LARYNX, StrelMll Wright. 



Woodcut, fig. 81. 



Acharadria larynx, — Strethill IVright, in Micr. Journ., vol. iii, n. s., p. 50, pi. v, 



figs. 7, 8. Hincks, Brit. Hydr. Zooph., p. 131, 

 pi. xxiii, fig. 3. 



TROPHOSOME. — Htdrosome attaining a height of ahout a quarter of an inch ; 

 HYDROCAULUS " Spirally twisted." Hydranths with from four to twelve tentacles in 

 the proximal verticil, and from two to eight in the distal. 



GONOSOME.— Unknown, 



Colour. — Hydranths pale orange. 

 Habitat. — On stones in the sea. 

 JBathymetrical disfridutiofi.—hammavian zone (?). 

 Locality. — Ilfracombe ; Dr. S. Wright. 



The little hydroid on which Dr. Wright founded his genus Acharadria was discovered by 

 him on stones along with Caryophyllia Smifhii, but from what part of the very wide bathy- 

 metrical range of the Caryophyllia his specimens were procured he does not tell us. He informs 

 us that the Acharadria resembles Tiibularia larynx in habit. 



I am indebted to Mr. Rotch for an opportunity of examining a little solitary hydroid which 

 had made its appearance in his aquarium, and which has afforded me the subject of the annexed 

 woodcut (fig. 81). It corresponds in all characters of generic value with the Acharadrium 

 larynx as described by Wright. Prom AVright's hydroid, however, it differs in its absolutely 

 simple stem, and in the absence of the spiral twisting given as a character of A. larynx. The fili- 

 form tentacles were ten in number, and the capitate tentacles five. The former possessed con- 



