Prof. J. C. Schjédte on Pediculus. 213 
Souleyet, ‘Voyage de la Bonite, Zool.? 1841.  Limneus 
Luconiensis. 
Pfeiffer, ‘Proc. Zool. Soc. 1845.  Amphipeplea Cumingi ; 
figured afterwards (as 4. Cumingiana) in the ‘ Novitates Concho- 
logice,’ pl. 2. figs. 3, 4, and in Ktister’s ‘ Continuation of Chem- 
nitz, Limneeacea,’ pl. 10. figs. 17 & 18. 
I suppose these all to be the same species, and identical with 
one which the Berlin Museum has received from Mr. Jagor ; 
but one of its principal characters, the deepened suture, is not 
well expressed in Pfeiffer’s figure. Beck introduced the name 
without any description; therefore the species cannot be re- 
garded as duly established by him, which, in fact, was done by 
Souleyet. Beck refers to the saine species, with some doubt, 
the Limneus imperialis, Lea: this (published in 1837, in the 
‘Transactions of the American Philosophical Society at Phila- 
delphia,’ vol. v. p. 81, pl. 19. fig. 73) would be the oldest specific 
name, if it should prove to be the same species; but the figure 
is either very bad or disproves this supposition. As to the ha- 
bitat, Lea supposes, with some doubt, the shell to be South 
American ; but as, especially in this paper, almost all the foreign 
localities given by this author (except North America) have 
since proved to be erroneous, no dependence can be placed on 
his statements. 
XX1V.—On Phthiriasis, and on the Structure of the Mouth m 
Pediculus. By Professor J. C. Scuséprr*. 
Tuar Pediculi are possessed of mandibles and able to bite is an 
opinion which seems not unlikely to be adopted by the naturalists 
and physicians of the present day. I expect, however, that 
naturalists, after renewed investigations and more careful con- 
sideration, will all sooner or later agree that this opinion is not 
only false in itself, but incompatible with the simplest, most 
elementary, and most certain principles of the morphology of 
Arthropods; and physicians will, 1 am sure, be not a little 
pleased to get the ancient monster “ Phthiriasis” placed on 
“the retired list,” in company with other griffins and dragons, 
the offspring of ignorance. The many old and new fabulous 
and confused accounts of cases of phthiriasis could not by them- 
selves keep alive a belief in its actual existence ; and that such a 
belief is still entertained is merely due to the notion that the 
mouth of Pediculi is adapted for biting, enabling them to eat their 
* Translated from the Danish original in ‘ Naturhistorisk Tidssknift,’ 
ser. 3. vol. ili. p. 48. Copenhagen, 1864. 
