Revision of the (reniw Lonianotus. 213 



ranging from 8 to ^ incli made in the following year. These 

 specimens vary considerably in colour. Two of those 

 captured in 1889 are marbled brown like L. marmoratus, the 

 third and largest is much lighter in colour, a pale fawn tinged 

 with red, while the specimens taken in 1890 are '' pale trans- 

 lucent orange." The sheath-margins of the rhinophores vary 

 too. They are simple in the smaller 1889 specimens, while 

 the larger one has " five or six blunt prominences or tubercles/'' 

 Of those captured in 1890, the larger specimens have sheath- 

 margins " produced into 4, 5, or 6 somewhat irregular pro- 

 cesses of either simple pa]nlla-like digitate or compressed 

 triangular form,'''' the smaller specimens have the sheath- 

 margins simple. From a study of these specimens and of 

 the descriptions of the six species of the genus established by 

 Italian and British authors Mr. Garstang is led to reduce all 

 to a single species, to which he assigns Verany's name 

 L. genei. He considers that the form of the tentacle sheath- 

 margin may vary in this genus as it appears to vary in 

 the allied genus Tritonia, and attributes the absence of 

 lobing in the margins of L. marmoratus to immaturity of the 

 specimen described by Alder and Hancock. Garstang is the 

 first to draw attention to the characteristic mode of swimming 

 of this species by a lashing of its body from side to side. 



1892.— Mr. F. W. Gamble describes, in the Ann. & Mag. 

 Nat. Hist., a nudibranch ^ inch long dredged in the preceding- 

 year in Plymouth Sound. It resembles C. marmoratus in 

 colour, but the sheath-margins have five papillce. Having 

 kept this animal living for some weeks, he not only notes its 

 peculiar mode of swimming, but observes that the papillae 

 both of the sheath-margins and of the pleuropodium are 

 capable of contraction and dilation. Following Garstang's 

 lead, he names this specimen L. genei. 



1896. — Mr. Gamble records, in the ' Irish Naturalist ' 

 (vol. V. p. lo3), the finding in the previous year at Valentia 

 Harbour, S.W. Ireland, of a stranded specimen of L. genei 

 2 inches long. 



1900. — Mr. W. I. Beaumont, in a Report on the Opistlio- 

 branchiate Mollusca of Valentia Harbour (Proc. R. 1. Acad, 

 ser. 3, V. p. 842), rejects Mr. Gamble's identification of the 

 large specimen found stranded in 1895 with Verany^s L. genei. 

 He places this Valentia specimen, as well as two other large 

 specimens he had recently found at Plymouth, under Thomp- 

 son's L. portlandicus , whicii he equates with Norman's 



