142 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



2. Ibid., " Report on the Nudibranchiata " : Challenger Expedition, vol. x, 

 1884. 



3. Ibid., "Die Opisthobranchien" from " Reports on the Dredging Operations 

 off the West Coast of Mexico, and in the Gulf of California in charge of Alexander 

 Agassiz carried on by the U.S. Fish Commission Steamer ' Albatross ' during 

 1891 " : Bull. Mus. Comp. Zool. Harvard, vol. xxv. No. 10, October, 1894. 



4. Cockerell, T. D. A., and Eliot, C, " Notes on a Collection of Calif ornian 

 Nudibranchs " : Journ. Malacol., vol. xii, 1905. 



5. Cooper, J. S., " On New or Rare Mollusca inhabiting the Coast of California. 

 No. II " : Proc. Calif. Acad. Nat. Sci., vol. iii, pt. i, 1863. 



V. On the Family Doriopsid^ (Doridopsid^). 



Pease in 1860 (19, p. 32) created a. new genus which he termed 

 Doriopsis, but the definition that he gave was not a very concise 

 one. Four years later Alder and Hancock (2, pp. 124-130) 

 established another genus Doridopsis, and in view of its peculiar 

 characters separated it ofi as a distinct family, the Doridopsidae. 

 It is closely allied to the Dorididae, but among other differences is 

 decidedly noteworthy in lacking a radula, while this organ is well 

 developed in the other family. This raising to family rank was 

 adopted by Hancock in 1865 (16, pp. 189-207) and by all subsequent 

 workers. Pease in 1871 (20, p. 279) reaffirmed his genus Doriopsis, 

 maintaining that it was slightly different from that of Alder and 

 Hancock, and proposed for the latter the name Haustellodoris. As 

 Bergh points out, however (1875, pp. 82-94), there is not much doubt 

 that all Pease's species would fall within Alder and Hancock's 

 genus, a statement with which Abraham (1, p. 240) is in agreement. 

 Thus what Alder and Hancock virtually did was to redefine the 

 genus more accurately. The validity of the genus and family is not 

 now questioned, but the name appears in dispute. It is obvious 

 that Pease's name has priority, and it was adopted by Bergh in a 

 series of papers from 1875 to 1884 (3-8). Abraham (1, p. 240) adopts 

 Alder and Hancock's name, stating : " We cannot follow him 

 {i.e. Bergh) in adopting ' Doriopsis ' as the generic name, not only 

 because none but Mr. Pease's own species, about which we cannot 

 always feel sure, will fall under that species as defined by him, 

 but also because the root of ' Doris ' is ' Dorid ' and not ' Dori ', 

 so that ' Doridopsis ' is more correct etymologically than 

 ' Doriopsis '." Eliot (13, p. 660, and 14, p. 7, etc.) also employs 

 the former of these two names. 



In answer to the first of Abraham's objections, it may be pointed 

 out that it not infrequently happens that the definition of a genus as 

 originally given has to be modified, usually to exclude but sometimes 

 to include other forms. The second is not a strong objection either, 

 for we are not, it may be unfortunately, primarily concerned with 

 questions of etymology, and it would not be difficult to cite cases 

 vvhere the names of genera and species are etymologically incorrect. 



It seems obvious that the constituent species of the two genera 

 are almost identical or, at any rate, can be jnade so by a slight 



