4 
THE VOYAGE OE H.M.S. CHALLENGER. 
length of the worm. The intestine leads anteriorly into a diverticulum, which has a 
distinct lumen, measures 078 mm. in length and 0'036 mm. in breadth, and lies 
anteriorly on the dorsal side of the oesophagus. The oesophagus, lying in the ventral 
side of the animal, is also continued backwards into a caecum lying below the intestine, 
and measuring 1'86 mm. in length by 0 072 mm. in breadth. The lips bear dentigerous 
ridges, and between them there are accessory lips. The upper lip is quadrangular with 
rounded anterior angles, it is 0'043 mm. in length and 0’066 mm. broad; the outer 
surface is flat, the inner gives off two rounded processes, which extend outwards and 
forwards, and protrude terminally on either side below the outer surface. The accessory 
lips are hook-shaped and bent inwards ; they are but slightly smaller than the principal 
lips, from which they are markedly distant. The tail end is conical and pointed. The 
two uniform sabre-shaped cirri of the male are 7 '2 mm. long, and are protruded for about 
6 mm. They can be recognised with the naked eye, and to this the specific title obviously 
refers. Of postanal papillae there are four median, and somewhat towards the ventral 
surface three lateral, while in front of the anus there is a variable row of thirty-eight to 
forty or so. 
The largest female was 24 mm. long and IT mm. broad. The vulva is situated about 
the boundary between the first and second quarter of the body, dividing the latter in the 
proportion of 5 to 13. The ova are spherical, the shell measures 0 , 0049 mm. in thick- 
ness, and is considerably distant from the yolk. It exhibits a very beautiful marking, 
due to regular, uniformly distributed, minute, shining elevations. The diameter measures 
0‘072 mm., while that of the yolk is 0’042 mm. 
Ascaris spiculigera was first described by Rudolphi, 1 and has been subsequently 
observed by a great number of naturalists. The hosts are very numerous 2 — Mergus mer- 
ganser and Mergus serrator, Pelecanus americanus, Pelecanus onocrotalus, Pelecanus 
tetrarhynchus, and Pelecanus fuscus, Carbo brasiliensis, Carbo cormoranus, Carbo 
cristatus, Carbo dilophus, Carbo graculus, and Carbo pygmseus , Plotus anhinga, Lestris 
pomarinus, Larus tridactylus, Colymbus arcticus, Colymbus rufogularis , and Colymbus 
septentrionalis, Podiceps auritus, Podiceps dominicensis, and Podiceps minor, Uria 
troile, Alca tor da. The stomach and oesophagus are infested. The best descriptions are 
those of Dujardin 3 and Schneider. 4 The geographical distribution is remarkably ex- 
tensive, for the species occurs in Europe (Germany, Scandinavia, Austria, Sardinia, 
France), in Asia (Turkestan 5 ), in Africa, in America (Brazil), and in the Antarctic 
region. 
1 Entoz. Hist. Nat., Amstelsedami, t. ii., 1808-1810, p. 168. 
2 Von Linstow, Compendium der Helminthologie, Hannover, 1878, pp. 162-178. 
3 Loc. cit., pp. 206-208. 
4 Monographie der Nematoden, Berlin, 1866, p. 45, pi. i. fig. 14. 
5 Von Linstow, Fedtschenko’s Journey in Turkestan, Soc. Nat. Hist. Moscow, sec. 18, vol. ii. pp. 3, 4, 1886 (in 
Russian). 
