PACKARD.] TEANSFORMATION OF ARTEMIA. 511 



segments of Branchipus; of this no indications occur in literature. 

 That Artemia salina observed by J0I3- has eight apodous abdominal 

 segments with a very prolonged last segment can be seen from Joly's 

 illustrations, and also from this, that he counts six apodous abdominal 

 segments without including the two first apodous abdominal segments 

 which bear the external sexual organs. According to Rathke, who ob- 

 serv^ed alcoholic specimens of Artemia milhausenii [Art. ,mlina Eathke), 

 the postabdomen is indistinctly divided into segments; he did not indi- 

 cate how many segments there are. Our degraded generations of 

 Artemia salina with the ch aracter of Artemia m llhaMseni i ha ve j ust as many 

 apodous abdominal segments as Artemia salina, onlj- the articulation 

 is more distinct. In the description of Artemia arietina S. Fischer and 

 Artemia h'oppeniana S. Fischer nothing was said about the number of 

 apodous abdominal segments. Grube very incorrectly states the num- 

 ber of apodous segments in Artemia as being sis, incorrect, for because 

 right after in another diagnosis he correctlj' mentions in his subgenus 

 Branchipus nine apodous segments, thus showing which segments of 

 the abdomen he considers as apodous. Joly gave occasion for this 

 conclusion in omitting the two first apodous segments of the abdomen, 

 which m Artemia., as well as in Branchipus, bear the external sexual organs. 

 In the other mostly examined alcoholic specimens of Artemia, the artic- 

 ulation is not very plain to see. In this regard Branchipus oudneiji Lie- 

 vin [Artemia oudneyi Baird's) deserves attention, under which name an 

 Artemia from a salt lake in Africa was described by Dr. Lievin.^ This 

 African form has in the illustrations eight apodous abdominal segments, 

 of which the first only bears the external genitals, the last being short, 

 at least shorter than the preceding. Although this form, as in Artemia, 

 has eight ajjodous abdominal segments, it can nevertheless in this pro- 

 portion be included neither with the genus Artemia nor with the genus 

 Branchipus. But the illustration now does not correspond at all with 

 the description of the posterior part of the body of this Artemia. It 

 is said in the description^ that the specimens examined had laid a long 

 time in alcohol, and that therefore the number of abdominal segments 

 could not exactly be determined ; that the abdomen of some specimens 

 answered as if to one segment only, while in others four could be distin- 

 guished, again, in others five segments; but from the fifth in the others 

 they could not be distinctly seen. Dr. Lievin considers the presence 

 of eight abdominal segments as probable. Here the author u.nderstands 

 as abdomen only the whole of the upodous abdominal segments. Ac- 

 cordinglj", the number of apodous abdominal segments of this Artemia- 

 form, and also their proportion to each other, is considered as unknown. 

 It appears to me that with the absence of certain characters in ylr/e- 

 mia for distinction from Branchipus, we must assume eight apodous ab- 

 dominal segments. Of these the first two bear the external genitals, 

 but the last, terminating with a furca, is nearly twice as long as the 

 preceding, and is homologous with the two last apodous abdominal 

 segments in Branchipus. The latter possess at the end of the abdomen, 

 besides these segments, also abdominal appendages, mostly separated 

 from the last segment by an articulation. In Artemia the last abdomi- 

 nal segment is only somewhat shorter than the double length of the 

 penultimate segment, sometimes even a little longer. Here I have to 

 remark that in young, though fully developed specimens, the relative 

 length of this segment is more considerable than in old ones, as the 



iLiev.in, " Branchipus oudueyi, the Tozzcau worm," in "Feueste Schrifteu tier Natar- 

 forschtiuden Geselesch. zu Daiizig." Vol. V. 

 ^Loc. cit., pp. 8 to 9, 



