262 BOPYRID2. 
or neck with the hind part or matrix, which is exarticulate or sacciform, 
kidney-shaped, destitute of appendages. 
Length of male, one-tenth of inch ; female, (2) 
Liriope pygmea. H. Raruxe, Reise Bemerk. aus Skand. in Neust. 
Schr. Naturf. Ges. Danzig, tom. 2, p. 105—110 
(1841). Nova Acta Acad. Ces. Leop. Nat. 
Curios. tom. 20, p. 244, pl. 1, figs. 8—12. 
LiuugEBorG, Liriope et Peltogaster, in Nova Acta 
Reg. Soc. Upsal. ser. 3, vol. iii. p. 6, pl. 1, figs. 
1—23 (1859). Suppl. to ditto in ditto, pl. 6, 
figs. 1, 2 (1860). 
Oniscus squilliformis. Paunas, Spec. Zool. fase. 9, p. 50% Cavorint, 
Memoria sulla Generaz. dei Pisci e dei Granchi, 
transl. Erzeugung der Fische u.d. Krebse, pp. 164, 
165, pl. 2, figs. 18 m, n, r, r. 
Tue history of this species has been remarkable, nor 
can it yet be regarded as free from difficulties. Cavolini, 
as quoted above, first described and figured two different 
crustaceous animals (one of which he doubtingly referred 
to the Oniscus squilliformis of Pallas) which he had 
found parasitic within a sac attached to the tail of a crab 
belonging to the genus Portunus or Carcinus. In 1839, 
Rathke found in the Norwegian Sea, upon the bodies of 
Carcinus menas and Pagurus Bernhardus, two species of 
vermiform parasites, which he regarded as belonging to 
the Entozoaria (but which have since been proved, by 
their transformations, to belong to the Cirrhipeda), and 
which have subsequently been described under the names 
of Pachybdella Carcini * and Peltogaster Paguri. 
Within the body of the latter of these two parasites 
Rathke found eight minute crustaceans, which he con- 
sidered had been devoured by the Peltogaster, and which 
he described under the name of Liriope pygmea, referring 
them to the order Amphipoda, unaware that the generic 
* Professor Bell, in his volume on the Stalk-eyed Crustacea, p. 108, de- 
scribes the female of this parasite (Pachybdella carcini) as infesting Por- 
tunus marmoreus even to a greater extent than Carcinus menas. 
