252 PKOF. ALLMAN ON NBW GENERA 



St. John, of H.M.S. ' Silvia.' It was submitted to me for deter- 

 mination by Mr. J. Grwyn Jeffreys, by whom it is destined to 

 form part of the collection of the British Museum. It consists 

 of seven species ; and not one of these has been hitherto described. 

 They are referable to four genera, of which two, namely Camjpanu- 

 laria and Thuiaria, are well represented in the European seas, 

 while two are now for the first time defined, and, so far as I 

 know, have no representatives elsewhere. 



This collection, though small; is thus of special interest, coming 

 as it does from a region whose Hydroid fauna has been hitherto 

 entirely unexplored, and which, I am strongly induced to believe, 

 constitutes a distinct and well-defined area in the geographical 

 distribution of the Hydroida. 



To Mr. Busk I am indebted for a collection of calyptoblastic 

 Hydroids, consisting entirely of dried specimens or of specimens 

 which, after having been dried, had been mounted in liquid for 

 the microscope. It contains a large number of species : many 

 of these have been already examined and described by himself; 

 many others he has also examined, designated by MS. names, 

 and, in many cases, figured, so that his very careful and accurate 

 work only awaits publication. Others, again, hitherto unexamined, 

 he has liberally intrusted to myself; and these are described and 

 figured in the present paper. 



Erom Mr. Holdsworth I have received a collection of dried 

 specimens, made on the shores of (/eylon. It contains several 

 new and interesting species, chiefly belonging to the Aglaophenian 

 section of the Plumulariidae. 



Lastly, a small collection of Hydroida and Polyzoa was made 

 by the Eev. A. E. Eaton during a yacht voyage to Spitzbergen. 

 The specimens were collected in the Spitzbergen seas, and were 

 placed by Mr. Eaton at my disposal. Among the Hydroids, 

 however, of this collection there is only one specimen sufficiently 

 well preserved for determination. 



HYDROIDA GYMNOBLASTEA. 

 BOUQAINVILLIID^. 



Pjjkigonimus. 

 Perigonimus multicornis. Plate IX. figs. 1, 2. 

 TropJiosome. Hydrocaulus attaining a height of about two inches, 

 springing from a creeping network of hydrorhizal tubes, not 



