1908] Decapod Crustaceans. 38 
the chela is still unserviceable as å prehensile or defensive organ 
(fig. 3 1st pereiopod of a larva 11 mm. long, fig. 4 of åa full-grown 
individual). 
The larval-stage described by Kornspen is rather more advanced: 
vitellus is absorbed, armature on carapace has begun to appear, 
&e., &e.; so that we may undoubtedly conclude that between the 
stage found by Korr»erL and that described by the author in the 
Bergens Museum's Aarbog one moult at least has taken place. 
The development of the ova in the individuals secured during 
the expedition of s/s "Michael Sars” seems to have. been of a 
simultaneous character. Kornr»eL states that in the case of one 
motner numerous young were found in addition to two large ova 
whose diameter was 3.5 mm. So that it would seem as if the larvae 
were hatehed practically simultaneously: and we have reason to 
believe that during their stay beneath the body of their mother they 
undergo at least one moult. | 
In the two genera ot Anomura, Lithodes and Galathodes, SARs 
has shown that there is å very brief metamorphosis; and in both 
these genera, as in the genus Scleroeramgon, the ova are remarkabie 
for their large size. The Caridean genera Oryptocheles and Bytho- 
caris are also characterised by more than ordinarily large ova, and 
for these genera Sars has shown us å complete want of post- 
embryonie stages: since the young come out of the ovum with all 
their limbs developed, and correspond in all essentials with the full- 
grown animal. 
However the extremely brief metamorphosis of Lithodes and Gala- 
thodes is essentially different from that of the larvae of Scleroerangon. 
In the two genera of Anomura the larvae move freely about in 
the water and are furnished in the first post-embryonic stages with 
special exopodites on the two foremost maxillipeds which are speci- 
ally adapted for use as swimming organs and are afterwards gradu- 
ally metamorphosed. The larvae of Scleroerangon (ferox) lead å 
*sedentary” life in the first post-embryonic stages and have their 
limbs accordingly specially arranged for elinging, particularly those 
of the 4th and 5th pereiopods which subsequently become converted 
into true ambulatory organs. 
The development and existence of the larvae of Scleroerangon 
are very similar to what we find in the case of the crayfish 
Astacus fluviatilis, in which however the young leave the ovum in 
a less fully developed state (the Ist pair of pleopods is wanting) 
