the finih>i 



Studies oil niuriiio Ostiuuoil.s l(i3 



a closer study of the inorphology of these animals and the main features of this became rather 

 well known comparatively soon. 



At first rather serious mistakes were made in interpreting the limbs, the organs which, Tin- interpniutwn •,/ 

 after the shell, quite naturally aroused the greatest attention; this is, of course not so surprising 

 when one remembers the frequently peculiar type of these organs, how closely together they 

 are situated and the small size of the forms investigated. 



Thus H. MlLNE Edwahus in his work of 1840 denotes these organs as follows: „antenne 

 superieure pediforme" (= first antenna), ,,patte natatoii-e" {— second antenna), ,,anteime 

 inferieure" (= mandible), ,,mandibule" (this organ is interpreted by C. Claus, 1873, p. 214 as 

 ,,einen paarigen Seitenfortsatz der Oberlippe"; it seems to me impossible to decide with certainty 

 whether this assumption is correct or whether the organ described by MlLXE EDWARDS may 

 possibly be the maxilla), ,,machoire de la premiere paire" (=fifth limb), ,,machoiredeladeuxieme 

 paire" (presumably the sixth limb; it seems to me rather improbable that it should be the 

 maxilla; if it were so the sixth limb, which is rather conspicuous, would not have been observed 

 at all) and ,,patte ovifere" (= seventh limb). The descriptions and drawings of these organs 

 are extremely incomplete and uncertain. This author writes on p. 410: ,,Les deux paires 

 d'antennes .... constituent des rames natatoires ..." — In W. Baif^D's work of 1847 

 we find the following interpretation: ..anterior anteima" (= the mandible), ,, natatory foot" 

 (= the second antenna), ,, second pair of antennae" (= the maxilla), ,,the mandible I did not 

 succeed in seeing", ., -first pair of jaws'" (= the fifth limb), the sixth limb is not mentioned, the 

 ,,oviferous foot" (=^ the seventli limb). Compared with this interpretation the one we find 

 in the same author's work of 18o() a may be considered as an advance, even though 

 a small one: ,, first pair of antennae" (— first antenna), ,, second pair of antennae" (—man- 

 dible), ,, natatory foot" (= second antenna), ,,the mandible is a flat plate armed at its extremity 

 with three or four sharp teeth", p. 177, (it is difficult to decide which limb or part of a 

 limb is referred to; it may possibly be a part of the fifth limb), ,,the first ])air of jaws is 

 composed of a large bcxly with three or four appendages, like fingers, armed with stout cilia, 

 and having attached to each a large branchial plate", p. 177 (here too it is difficult to decide 

 which parts are referred to, possibly the sixth limb with the vibratory plate of the fiftli; it 

 seems improbable that it should be merely parts of the fifth limb that are referred to, one reason 

 among others being that it is certainly a species belonging to the genus Philoinedea that has 

 formed the basis for these statements), ,, second pair of jaws" (=- maxilla), and ,,oviferous foot" 

 (seventh limb) — S. FiSCHER may be said to have been still more unfortunate in his work of 185;): 

 ,,erste Antenne" (-^ first antenna), ,,zweite .\ntenne" (== mandible), ..^landibel" (- the fifth 

 limb or the masticatory part of the fifth limb + the sixth limb), „Maxille" (— maxilla), 

 „hinter ihm" (maxilla) ,,liegt die ziemlich groBe und starke Kieme" (either the vibratory plate 

 of the fifth limb or the sixth limb) ,,und unmittelbar unter derselben zwci nach riickwart.s 

 gerichtete, mit starken befiederten Borsten versehene Palpen" (^ the seventh limb?). This 

 writer is especially unfortunate in the interpretation of the second antenna; the exopodite 

 of this limb is interpreted as the ,,erste FulJ". its endopodite as .,zweiter FuB". FisciiKR also 

 surpasst^s the two first-nametl writers in the incompleteness and uncertainty of the descriptions 



