ENTOMOSTRACA, SIPHONOSTOMA. 
203 
lated ; thorax 4-articulated ; thoracic feet simple, flat, triangular, terminated 
by a claw ; two-pointed corneous prolongations at the extremity of the ab- 
domen. — A. rufus, sp. n., found in the interior of a social Ascidian. [Rectius 
Haplopus, but then preoccupied.] 
SIPHONOSTOMA. 
The parasitical Crustacea living on Annelids have been among 
the last subjects of study to two observers of first rank, both now 
deceased, M. Sars and E. Claparede. The latter has revised 
the known genera from the original descriptions, and in com- 
parison with his own observations. lie arranges them as 
follows : — 
1. Pcecilostoma, Thorell (Ergasilidci) \ — Selins, Erdyer, 1837; Terehellicola, 
Sars, 18G1 ; Sabellijjhilus, Sars, 1861 ; Chonephilus, Sars, 1861. 
2. Siphonosto7na proper ( Caligidcc and Lernceidcc) : — Sileniiwi, Krdyer, 1863 j 
Jlo'pgllohins, Steenstrup and Liitken, 1861, perhaps the same as the pre- 
ceding ; Sahcllacheres, Sars, 1861 ; Nereicola, Keferstein, 1863 5 and Che- 
lonidiformk, Hesse, 1869. Ann. Sc. Nat. (6) xiii. pp. 1-9. M. Sars adds 
two new genera, and identifies Selins with Sile7tiuni, Kundsk. Christ. Faun, 
p. 1. 
Ergasilidas. 
Bo7nolochus helones (Burmeister). The subject of a careful morphological 
and anatomical description by Rob. Hartmann, Arch. Anat. Phys. 1870, 
pp. 116-163, pis. 3, 4. He found this parasite on the inside of the opercula of 
the Sea-pike or Gar (Belo7ie), as well in the Mediterranean as in the German 
Sea.— R. ostracio7\is, sp. n., Richiardi, Arch. p. Zool. ii. pp. 47-69, pi. 1, fully 
described, from the inside of the gill-opening of OstracioTi co7'7iut7is, from 
Mozambique. 
SahelUijliilus sa7'sii, sp. n., Claparede, Ann. Sc. Nat. (5) xii. p. 10, pis. 7-16, 
Naples, on the body of Spirogr aphis spalla7iza7iii. The species is fully de- 
scribed, and the genus stated to be very nearly allied to Licho77iolgus, 
Thorell. 
CaLIGIDvE. 
Caligns [?] hijalhms, sp. n., Czerniavski, Mater, zoogr. Pont. p. 66, pi. 8. 
figs. 46,46, free-swimming between Algoe. 
Silc7iiu7n c7'assi7'ostris [-c], sp. n., M. Sars, 1. c. p. 2, pi. 8. figs. 10-16. Corpus 
fe7ni7ice sacciforme, subglobosum, album, levissimum, antennis pedibusque 
destitutum. Acetabulum in media fere longitudine corporis situm, tubulo- 
sum, valde crassum, crassitudine tertiam ferme partem latitudinis corporis 
requante. Sacculi ovigeri ignoti. Mas minutissimus fomia Cijclopis, ce- 
phalothoracelatiore, quadriarticulato, antice in acetabulum elongatum conico- 
acuminatum producto ; cauda graciliore, triarticulata, appendicibus duabus 
(furca) brevibus crassiusculis, setis 3 natatoriis armatis prfedita. Antennae 
nullae. Maxillipedes duo triarticulati, articulo ultimo hamato. Tria paria 
pedum natatoriorum, biramosorum, ramis uniarticulatis, exteriore ad apicem 
setis natatoriis 6, interiore illo breviore setis 2 praedita. Drobak, near Chris- 
tiania, on the back of Poly7ioe dispar. 
