572 CLASS ix. 



marine creatures appears to be a mistake 1 . They are dull animals 

 living on the beach under stones, or on marine plants. They 

 undergo, according to the observations of KROEYER, a remarkable 

 metamorphosis, and have at first only two pairs of short feet, and a 

 short, thick, undivided body. Afterwards a third pair of feet, still 

 short, appears, and only in a succeeding state is the fourth pair added 

 to them. 



That division of the body which lies in front of the first pair of 

 feet and bears the eyes above, is in some more, in others less dis- 

 tinctly distinguished from the first ring of the thorax. To this 

 division are attached on the under surface two filiform parts, consist- 

 ing of 7 11 joints, which in some species occur only in the female 

 and serve for the attachment of the eggs. In some species in front of 

 these are two pairs of other parts at the base of the conical sucker, 

 of which the first pair, shorter and broader, mostly forms a shear- 

 shaped nipper, the second is filiform, and consists of five, sometimes 

 of more joints, and is commonly denoted as a feeler (palpus). It 

 is worthy of remark that the first-named, the nippers or mandibulce, 

 occur also in the earlier imperfect state of those species which, in 

 the perfect form, are not provided with them. 



The hardness of the integument of these animals renders it less 

 probable that they breathe by the skin. Probably they have an 

 intestinal respiration, such as occurs also in other animals. 



Compare M. T. BRUENNICH Entomologia, Haffniae, 1764, 8vo. p. 84, with 

 the explanation of fig. 4 (Pycnogonum) of Tab. ; various figures are found 

 in MUELLER Zool. danica Tab. 119, in LEACH Zoolog. Miscellany, I. PI. 13, 

 19, SAVIGNY Mem. s. 1. Ani. s. v. I. p. 54, PI. v. fig. 3, GUERIN Iconogr., 

 Arachn. PI. 4, &c. 



G. JOHNSTON Mag. of Zool. and Botany, i. 1837 ; A. PHILTPPI Neapoli- 

 tanische Pycnogoniden in ERICHSON'S Archiv f. Naturgesch. ix. 1843, 

 s. 175 182, Tab. ix. figs, i 3; H. KROEYER Naturhist. Tidsskrift, m. 

 1840, pp. 2Q9 306, Tab. in. and ibid, new series, i. 1844, pp. 90 139; 

 H. D. GOODSIR On the specific and generic characters of the araneiform 

 Crustacea, Ann. of not. Hist. xiv. pp. i 4, PL I; DE QUATREFAGES Mem. 

 sur Vorganisat. des Pycnogonides, Ann. des Sc. not. 30 Sdrie, Tom. IV. 1845, 

 Zool. pp. 69 83, PI I. II ; DUJARDIN in Compl. rend. 1849. T. xxix. p. 28; 

 ZENCKER in MUELLER'S Archiv f. Anat. u. Phys. 1852, s. 379. 



A. Mandibles and palps (first pair of maxillae according to 

 KROEYER) none. Accessory feet (second pair of maxilla? KROEY.) 

 in females alone. 



1 FABRICIUS considered the parasitic crustacean, named by LINN^US Oniscm Celt, 

 to be a species of this genus Pycnogonum. 



