118 Eev. T. Hincks on Prof. Heller's Catalogue 



on the mode in which the calycles are disposed, whether alter- 

 nately or in pairs, seems to me to be merely artificial, and not 

 in any measure to represent the natm-al relationships of the 

 forms in question. A well-marked group, of which 8. poly- 

 zonias may be taken as the type, has been defined by Gray 

 under the name of Sertularella ] another, equally natural, 

 characterized by the peculiar structure of the reproductive 

 capsule (which is well exemplified in 8. rosacea), has been 

 constituted by Agassiz as Diphasia ; a third, to which the 

 Linnean name may be appropriated, will include the remain- 

 ing forms, whether they have opposite or alternate calycles, a 

 point in which the most closely allied species differ. Those 

 which have the calycles in pairs may, for convenience' sake, 

 be ranked as a subsection. 



8ertulana Ellisii is amongst the species recorded in the 

 Catalogue. It should be noted that this is the well-known 

 and widely distributed 8. polyzonias of authors, one of the 

 most cosmopolitan of the Hydroida. Heller adopts the opinion 

 of Milne-Edwards, that Ellis has figured two distinct species 

 under the name oi polyzonias ; and also follows him in assign- 

 ing the name Elltsn to the commoner of the two forms. It is 

 unfortunate that the new name should have been given to 

 the well-known species, while the old and classical designa- 

 tion has been reserved for a form which rarely occurs and has 

 attracted little attention. In my ^ History of the British 

 Hydroid Zoophytes ' (vol. i. p. 235) I have cited 8. Ellisii as 

 a synonym of 8ertularella jjolyzonias ; but, after a more care- 

 ful examination of Ellis's figures and description, I am dis- 

 posed to believe that Johnston was wrong in uniting them, 

 and that the erect variety, with ovate calycles and a plain 

 aperture to the gonotheca, is a well-marked species. At the 

 same time I have never found it myself, nor have I met with 

 specimens of it : but one of Ellis's figures is unimpeachable 

 evidence ; and variable as >S'. polyzonias is within certain 

 limits, it never, so far as I am aware, makes an approach to 

 the characters which he has so clearly represented in his 

 figure B. Couch records both the forms as occurring on the 

 Cornish coast, and regards them as sj)ecifically distinct 

 (Cornish Fauna, p. 17). But, while accepting Milue-Edwards's 

 species, I am strongly of opinion that the names should be 

 reapportioned — that the more common form, which was pro- 

 bably the one known to Linnseus, should bear the older name 

 [])olyzonias)^ and that the one which Ellis was the first to 

 figure should stand as aS'. Ellisii. 



Dynamena {Dij^Jiasia) pinaster. — The specimens thus 

 named, it is evident (from the description of the capsule and 



