Manchester Memoirs, Vol. xlvi. (1902), No. 16. 



XVI. The Luminous Organs of Pterygioteuthis 

 margaritifera, a Mediterranean Cephalopod. 



By William E. Hoyle, M.A., F.R.S.E. 



Read May i^lh. Received May 26tk, igo2. 



The species which forms the si ject of the present 

 communication was created more chan half a century 

 ago by Dr. Riippell, * under the title Enoplotenthis mar- 

 garitifera, and owes its trivial name to its most striking 

 character — a semicircle of pearl-like bodies, surrounding 

 the lower portion of the eyeball. Verany in 1S51 -f* figured 

 and described it, and two small specimens, apparently 

 referable to the same species, were obtained by the 

 "Challenger" Expedition;):. The form which Dr. Jatta has 

 included under this name in the Naples monograph || does 

 not appear to me to be correctly identified. 



It is evidently a form of somewhat rare occurrence ; 

 there are two specimens in the British Museum 

 from Dr. Riippell's collection from Messina, perhaps 

 the only locality where it has hitherto been obtained ; 

 and as Riippell's original examples are not, so far as I 

 am aware, in existence, these must be regarded as the 

 types of the species ; at all events they have the authen- 

 ticity of co-types. The species has recently been removed 

 by my friend Dr. Pfeffer ** to the genus Pterygioteuthis 

 Fischer, a step which I think quite proper, though it 

 certainly differs specifically from Fischer's type {P. giardi), 

 as I hope to show elsewhere. 



* Gio7n. Gab. Messina, vol. 26, p. 2, 1844. 

 t " Cephalopodes de la Mediterranee," p. 82, pi. 30, 185 1. 

 J " Report on the Cephalopoda collected by H.M.S. 'Challenger,'" 

 p. 171, pi. 29, 1886. 



II " Cefalopodi viventi nel Golfo di Napoli," p. 87, pi. 12, 1896. 

 •• " Synopsis der oegopsiden Cephalopoden," Hamburg, 1900. 



/une 24th, igo2. 



