Grust. 24 
DECAPODA (mACRURA). 
extremity of the cephalothorax covering the base of the antonnse and eye- 
stalks, the feeble antennae, and the nearly smooth surface of the cephalo- 
thorax ; therefore more resembling at first sight. P. gundlachij 
sp. n., Cuba, Martens, SB. nat. Fr. 1878, p. 131. 
Eryonidj:. 
Willemoesia [Zool. Rec. xi. p. 207] leptodactyla, Atlantic in 21° N. lat- 
and in 35° S. lat., 1900 fath., and crucifera^ Sombrero Island, West Indies, 
450 fath. ; genital opening of the male in the latter at the base of the 
fifth pair of feet, as usually, but in the former at that of the third ; both 
species described and figured, and the relation to the fossil Eryon pointed 
out ; Willemoes-Suhm, Tr. L. S. (2) i. pp. 50-56, pi. xii. fig. 10, & pi. xiii. 
The first of these species dredged near Juan Fernandez, 1375 fath. ; C. S. 
Bate, Ann. N. H. (5) ii. p. 280, pi. xiii. figs. 4 & 5 ; male organs described, 
id. 1. c. p. 486, woodcut. 
. C. S. Bate discusses the peculiarities of the genera Polycheles (Heller), 
Pentacheles, g. n. (infra), and Willemoesia (Grote, 1873), and enumerates 
their species, giving geographical and bathymetrical distribution, rang- 
ing from 310 (near Patagonia, only 120) to 1900 fath. They probably bur- 
row in the soft mud of the deep sea ; Rep. Brit. Assoc. Dublin, 1878, 
pp. 661-564, and Ann. N. H. (5) ii. pp. 273-282. 
Polycheles crucifer (Willemoes-Suhm, as Willemoesia), West Indies, 
450 fath., helleri, sp. n., Kermadec Island, 520 fath., and haccatus, sp. n., 
Fiji Islands, 310-315, fath. ; id. Ann. N. H. (5) ii. pp. 277 & 278, the first, 
pi. vi. fig. 8. 
Pentacheles, g. n. All thoracic feet chelate ; eyes in a notch of the 
carapace, projecting. P. Icevis, sp. n., Philippine Islands, 500 fath., 
suhmi, sp. n., Patagonia, 120 fath., gracilis, sp. n., Fiji, 210-610 fath., 
obscurus, sp. n., New Guinea, 1070 fath., auriculatus, sp. n., Fiji, 610 fath., 
and euthrix, sp. n. (Willemoes-Suhm, MS.), New Hebrides, 315 fath, ; id. 
1. c. pp. 276 & 278-280, the last pi. xiii. figs. 1-3. 
A. M. Norman thinks that perhaps PewtocAeZes may perhaps be the other 
sex of Polycheles ; Ann. N. H. (5) ii. pp. 382 & 383. Bate replies that 
he has examined males and females of all three genera ; tom. cit. p. 484. 
Astacid^. 
T. H. Huxley (P. Z. S. 1878, pp. 752-776) has examined the structure 
and position of the gills in the freshwater crayfishes. He distinguishes 
podobranchiae placed on the coxopodite, arthrobranchise on the articular 
membrane uniting the coxopodites to the thorax, and pleurobranchiae on 
the epimeron or side-wall of the thorax. A podobranchia is found on the 
second and third maxilliped and all the thoracic feet, except the last ; 
one or two arthrobranchife (one anterior, the other posterior) on the same 
limbs ; one generally on the second maxilliped ; two on the third maxil- 
liped and the first, second, third, and fourth thoracic foot. The posterior 
arthrobranchia of the fourth foot in Paranephrops and ParastacuSj the 
I 
