L 313 ] 



On the Genus Cumanotus. 



By 

 Sir Charles Eliot, K.C.M.a. 



(See Eliot on Coryphella heaumonti in Notes on some British Nudibranchs, Journ. 

 Mar. Biol. Assoc, vol. vii., No. 3, June, 1906, pp. 361-3 ; and Nils Odhner on 

 Cumanotus laticeps in Northern and Arctic Invertebrates, iii. Opisthobranchia. Kngl- 

 Svenslav Vetenskapsahademiens Handlingar. Band 41, No. 4, 1907, pp. 29, 80, and 

 101-2). 



In describing (I.e.) Coryphella beaumonti as a new species, I pointed out 

 that in many important characters it differs markedly from the other 

 known CorypheUcc, and might be made the type of a new genus. But 

 I did not create a new genus, thinking it might be well to examine 

 further specimens, both of this animal and of allied forms, before 

 deciding on its place in the classification. In the next year Odhner 

 created (I.e.) the genus C2cmanotus* to which Coryphella heaumonti is 

 certainly referable, and which is shown by his researches to be well 

 characterized. It is allied to Coryphella inasmuch as it has un- 

 perfoliate rhinophores, tentacular angles to the foot, a triseriate radula 

 and denticulate jaws ; but it also possesses the following special 

 characters : (1) The oral tentacles are very small and connected by 

 a cutaneous fold which runs across the head ; (2) there are several (at 

 least, as many as three) rows of cerata in front of the rhinophores ; 

 (3) the verge is deeply grooved, and there is a bursa copulatrix, the 

 entrance to which bears on its upper and lower margin a circular pad, 

 armed on the periphery with twelve small cones terminating in 

 hooks. 



In the specimen which I dissected, the reproductive organs were 

 much contracted, and I supposed these cones to be an armature on the 

 male genitalia, such as is not uncommon in aeolids ; but a dissection of 

 more specimens, as well as an examination of the animals in life, has 

 shown that Mr. Odhner is perfectly correct in describing the arrange- 

 ment as two pads placed at the entrance of the bursa copulatrix. 

 I have not seen the animals alive myself, but Mr. L. E. Crawshay, who 

 observed their movements in the tanks of the Plymouth Laboratory, 

 writes to me that : " Though in appearance the arrangement suggests 



* He says it is from Ku^ia, a wave, and vQitov, back ; Vjut if so, would not Cymanohis be 

 the more usual form 1 



