114 Di*. J. D. Macdonald on the xlnatomy of 



number to 96 ; and I would desire, consequently, to record it 

 as follows : — 



Cydonia vicina. 



Cheilomenes vicina, Bej., Cat. 4o9 (1837). 



circumjiexa (King), Id., ihid. (1837). 



Cydonia vicina, Muls., Securip. 440 (1851). 

 , Woll., Col. Hesp. 155 (1867). 



Hah. Sanctam Heleuam, teste cl. G. R. Crotch. 



I liave likewise a note from Mr. Crotch to the effect that 

 the Sjyhcer-idium dytiscoides of Fabricius is still preserved in the 

 Banksian collection, and that a friend of his who has recently- 

 examined it reports it to be totally distinct from the Dactylo- 

 sternum ahdominale^ being, in point of fact (as, indeed, I had 

 ventured to think probable) , a true Cyclonotum^ and one which 

 occurs also at the Cape of Good Hope. 



XIV. — On the Anatomy of the Nervous System of Diphyes, 

 affording p'esumptive evidence of the existence of a similar 

 System in the other forms of Oceanic Hydrozoa. By JOHN 

 Denis Macdonald, M.D.,'F.R.S., Staff-Surgeon of H.M.S. 

 ' Lord Warden.' * 

 While cruising off the coast of Portugal, a few hauls of the 

 towing-net brought up many specimens of a species o^ Diphyes 

 which I have not determined, as the suitable books were not 

 at hand ; this, however, may be readily done by referring to the 

 figure accompanying this paper. I very carefully examined 

 several of these animals (or, I am rather tempted to say, 

 animal forms) in relation to the received views of the struc- 

 ture and organization of the group to which they belong. In 

 some instances the two nectocalyces were nearly intact, while 

 in others they were separated, which is more usually the case. 

 This latter remark is also quite true of the parts of numerous 

 other oceanic Hydrozoa, which were quite problematical to 

 most students of zoology until Professor Huxley elucidated 

 their structure by independent research, which enabled him 

 also to render the results obtained by others more intelligible. 

 In the present species the proximal nectocalyx is about 

 twice as large as the distal one, sharp-pointed, three-sided, 

 and much laterally compressed at the free extremity, but 

 distinctly quadrilateral at the base, where two angular pro- 



* Communicated by the Director-General of the Medical Department 

 of the Navy. 



