1 66 BULLETIN OF THE BUREAU OF FISHERIES. 



HISTORICAL. 



The genus Lerruea was founded by Linnaeus in 1758, in the tenth edition of his 

 "Systema Naturae," with the three species, cyprinacea, asellina, and salmonea (p. 655). 



The species asellina, a salt-water form, has since become the type of the genus 

 Medesicaste, while the species salmonea, a fresh-water form, is the type of the genus 

 Salmincola. The species cyprinacea, another fresh-water form, thus becomes the type 

 of the original genus by elimination as well as by priority- 



In 1822 " Blainville founded his new genus Lernceocera, and gave as his first or type 

 species branchialis, which had been included by Linnaeus in his genus Lerncea in the 

 twelfth edition of the "Systema Naturae." Blainville also included in his new genus 

 a second species, cyclopterina, which later became the tj'pe of the genus Hcemobaphes. 

 His third species was new to science and he named it surriraiis for Dr. Surriray of Havre, 

 who sent him a specimen. But his description gave the egg strings as uniseriate, which 

 would exclude it from the genus, and in all probability it was identical with Lernceenicus 

 sprattcB. Of course Blainville had no right to add, as his fourth and last species, cypri- 

 nacea, the type of Linnaeus' genus Lerntea. 



We thus have the genus Lerncea established by Linnaeus in 1758, with cyprinacea 

 as a type and including the species branchialis (1767), and the genus Lernceocera estab- 

 lished by Blainville in 1822, with branchialis as a type and including the species cyprinacea. 



Curiously enough, in endeavoring to straighten this muddle, subsequent authors 

 have reversed the genera, and branchialis has come to be accepted as the type of the 

 genus Lern-cea, while cyprinacea was formally declared to be the type of Lernceocera by 

 Cunnington in 1914.* 



But Lerncea is the oldest genus amongst the parasitic copepods, and its ancient 

 prestige must be restored by giving it again its original type species and making it a 

 fresh-water instead of a salt-water genus. 



In 1832" Nordmann published a more complete description of L. cyprinacea, but 

 failed as Blainville had done to find the swimming legs. 



His paper was of great value, however, because it contained the description and 

 figures of a newly hatched nauplius larva, the first and the best that have ever been 

 published. 



In 1833'* Burmeister presented a second description of L. cyprinacea, illustrated by 

 good figures; he also showed that the species described by Nordmann was not cyprinacea 

 at all, but a species new to science, which he named esocina from its host. But he 

 regarded the two pairs of antennae as the anterior and posterior rami of a single appendage, 

 and he added one more to the list of those who had failed to find the swimming legs. 

 The swimming legs were first discovered by Briihl in i860 on a species which he named 

 Lernceocera gasterostei, but which was evidently the same as the one described by Nord- 

 mann, viz, esocina. 



In the following year Claus confirmed Briihl's discovery upon two specimens sent 

 him by Prof. Leuckart and called by the latter Lerncea gobina, but which Claus after 

 examination believed to be identical with Briihl's species. In addition he corrected a 

 mistake common to all previous investigators, by whom the two pairs of antennae had 

 been transposed, the anterior pair ha\'ing been called posterior and the posterior pair 



o Jour. Physique, vol. 95, p. 372-380. 437-447. ^ MikroRr. Beitrage. pt. 2. p. 133. 



' Troc. Zool. Soc. London, 1914, p. 819-S29. "• Acta Acad. Caes. Leop. Carol. Nat. Cur., vol. 17, p. 309. 



