!'\> IDA 



mbryonal and the larval stage, cannot be fully kt].t up with regard to the 

 ■ ■ i u.i.il mark ol distiuctiou (whethei the embryo has or has 



ery little importance, and nearl) rel rms, even species of the 



ttain to a different, sometimes very different development in the egg. Accordingly 

 it w m\ the metamorphosis in such forms as do not leave the egg until the) have 



ined their permanent shape This opinion and the interpretation of the larval development now 

 irrent have been expressed bj Korschelt a. Heider (1890) p. 662 seq: J >i ^ meisten 

 Pantopoden entwickeln sich mittelst Metamorphose thre Larven weisen gewohnlich drei Extremi- 

 st, doch verlassen einige in hoherei Ausbildung das Hi; so besitzen diejungen Pallenen') 

 beim Ausschlupfen bereits sammtliche Extremitaten und auch einige Arten der Gattung Nymphon 

 ichen schon im Ei diese hohere Entwickelungsstufe. Die verschiedenen Arten der letztgenannten 

 g differiren ubrigens in dieser Beziehung, da die Larven einiger beim Ausschlupfen nur vier 

 funf Extremitatenpaare aufweisen (Hoek). As will be seen from this quotation, Korschelt and 

 Heider found their statement especially on the examinations by Hoek, or recapitulate the principal 

 nts "i the description of Hoek as it is given in his last great work: Nouvelles etudes sur les 

 Pycnogonides (1881), p. 482 seq. 



But before I pass to my own representation of the developmental history I shall give a short 

 historical view of the most important works in this branch of study, and as we have already in 

 irn: Die Pantopoden des Golfes von Neapel (1881) a very copious literary survey, I may limit 

 myself t<> the following four authors: Kroyer, Dohrn, Hoek and Morgan. 



K. rover is the author to be named first, not only because he first of all has studied and de- 

 scribed larvae of the Pycnogonida, but also on account of his contributions being the most important 

 • we hitherto have got concerning the development of these animals. Already his 1 >m Pycnogo- 

 nidernes Forvandlinger 1 On the metamorphoses of the Pycnogonida 1 (1840) is of great importance, 

 but still more so is the series of representations of larval forms given on pi. 39 of the great, unfinished 

 French work of travel: Gaimard, Voyages en Scandinavie etc. (1849) to which never appeared 

 any text or explanation. As such an explanation may with regard to the Pycnogonida be taken 

 Kroyer's Contributions to our knowledge of the Pycnogonida , Bidrag til Kundskab om Pycnogo- 

 niderne eller Sospindlerne (1845). I" l ' K ' close of the third section of this treatise, on the metamor- 

 phoses of the Pycnogonida, I.e. p. 136 seq. Kroyer collects the laws that seem to regulate the devel- 

 opment of the Pycnogonida under 5 principal heads which may briefly be rendered thus: 1 The 

 -s through 3 stages. 2 The first stage is of a thick, swollen shape; filled with yolk 

 without any abdomen; with a proboscis; with cheliferous Kindbakker (mandibles); 

 with 2 pairs of feet. Eyes seem to be wanting. 3 In the second stage a third pair of feet 

 found, but they are short, and have only an indistinct articulation, or none at all. Eyes as well as 

 the cond pair of Kjseber (maxilles) can be distinguished, at least in some species. Some- 



tin* Ik substance- of the body is present, in which case tin young one passes this stage under 



I'll, species • >» this genus tli.it 1 have examined, .is will be 

 when tin thi ol ambulati have been developed and before the 



legS. 



