PROVISIONAL SPECIES. 271 



It occurs ill considerable abuiulauce on the west side of the Gulf of Spczia, on rocks which 

 are never uncovered by the sea. 



PROVISIONAL AND INDETERMINABLE SPECIES. 



Certain hydroids have been from time to time described whose probable, or at least possible, 

 place is in the genus Coryne ; but which from the fact of our as yet knowing only their tropho- 

 somes, cannot be assigned to this genus otherwise than provisionally ; while others, though 

 referred by their describers to Cori/ne, have been so very imperfectly described as to render their 

 determination impossible. 



Among those which arc in all probability correctly referred to this genus is the following : — 



Coryne nutans, Allman (provisionally). 



TB.OPHOSOME. — Hydrocaulus attaining a height of about four lines, mucli brauched ; branches 

 subalternately disposed, deeply and distinctly anuulated, the annulation of the hydrocaulus becoming less 

 distinctly marked towards the base. Hydranths depressed on one side of the stalk, so as to assume a 

 nutant posture; ovate, with about fifteen tentacles. 



GONOSOME unknown. 



The little coryniforiu hydroid here described was obtained in Burraforth Caves, Shetland, by 

 the Rev. A. M. Norman, who placed in my hands for e.xamination some specimens which had been 

 preserved in spirits. 



These specimens were entirely destitute of gonosome, and its determination cannot, there- 

 fore, be regarded as otherwise than provisional. The trophosome, however, was well preserved, 

 and one of its most characteristic features consisted in the drooping attitude assumed by the 

 hydranths, a feature which has suggested the name by which I have designated the species. 



Among provisional species must also be included the Coryne sessilis of Gosse.^ This is a 

 minute coryniform hydroid with undeveloped hydrocaulus, and with nearly colourless, very elon- 

 gated hydranths, having the tentacles more than forty in number, and arranged in about six 

 verticels. As the trophosome is the only part of the hydroid known, the determination of the 

 genus must be held ov.er until the discovery of the gonosome shall afford the necessary data. It 

 will then be most probably seen that the gonophores are phanecodonic, and that the liydroid 

 must consequently be removed from Coryne. Mr. Gosse himself, indeed, assigns to his determi- 

 nation of it only a' provisional value. He obtained it attached to a rock on the coast of 

 Ilfracombe. 



' Gossc, ' Devonshire Coast,' p. 208j pi. xiv, figs. 2, 3. 



