(I A.MM \uii).i:. 207 



jiair hiiviiip: the ciirpus and piopodos rather Ioniser than in tlic firet, 

 but otlitTwiso t'oriiied like tlu'in, cxct-pt that the indni is obli(iuo, not 

 convex, and defined by a small tooth, Pereiopoda havang the coxsd 

 of the fii'st two pairs as deep as their segments, of the last three 

 pail's about one-fomth as deep; basa of the last three pairs ovate; the 

 other joints generally spinous. Antepenultimate pair of pleopoda 

 longer than the penultimate ; penultimate scarcely reacliing beyond 

 the peduncle of the ultimate ; ultimate having the p(!duncle very 

 short, rami subequal, three times as long as the peduncle, — the 

 inner branch armed upon the internal margin with four or five 

 short equidistant spines and as many plumose hairs, one of each 

 being lodged in as many separate depressions ; the outer branch 

 has the lower margin fringed with fasciculi of short spinules. 

 Telson as long as the peduncle of the posterior pair of pleopoda, 

 and furnished A\-ith a few short stiff spines. 

 Length of Icelandic specimens, 1| inch; of British, |- of an inch. 



Hah. Arctic Seas, and all round Europe. Some large specimens in 

 the British Museum were presented by M. Drewsen. 



The colour of this species is generally of a bluish-green, mottled 

 with darker spots of the same, and a few widely dispersed spots of 

 bright red or scarlet ; these last, as far as my experience goes, may, 

 in the living animal, be confidently trusted in as diagnostic of the 

 species : one is situated upon the second, thii'd, and fourth segments 

 of the pereion, a small one on each coxa of the posterior pairs of 

 pereiopoda, and one upon each of the three anterior segments of the 

 pleon. Under the microscope the structiire of the integument is seen 

 to have a granulated appearance, while certain arrow-headed spines, 

 surrounded by art areola, appear to pierce the integument. Upon the 

 three anterior segments of the pleon is a curved row of minute cilia, 

 each cihum rising through a ring, the whole surrounded by an areola. 



Leach, in the ' Edinburgh Encycl.,' remarks that the females carry 

 their young about with them after their exclusion ; and I am enabled 

 to state, upon the authority of my valued correspondent Dr. James 

 Salter, that the larvte, after having quitted the pouch of the mother, 

 \\\\\ return to it again on being alarmed ; and that, until they have 

 acquired confidence, they accompany their mother in a small crowd as 

 she s\vims through the Trater. 



5. Gammarus fluviatilis. (Plate XXXVII. fig. 1.) 



Gammarus fluviatilis, Roesel, Itisectei^behistuiungen, iii. pi. 52*. 

 Gaiuiiiiinis Kceselii, Gcmii.s, Ann. drs Sc. Nat. 2 stir. iv. p. l^.'^*. 

 (iaiiiinarus aquaticus, Lvach, Linn. IVan.s. xi. p. .%U. 

 Gammarus fossanmi, Koch,I)eutschl.Crmf.,Myr. n. Arachn. li.T). no. I. 



Very iiiuili like G. Locu.<<ta. Eyes subreniform, black. Superior 

 * From M. -Edwards, H/.sf. des Crust, iii. p. 4r). 



