1888-89.] Dr O. v. Linstow on Pseudalius alatus. 17 
Ps. injlexus , Duj.,* in the bronchi, gullet, heart, veins, and ar- 
teries of Phoccena communis. 
Ps. minor , Kuhn,* in the cavum tympani, a cavity beneath the 
eyes, the bronchi, heart, and veins of Phoccena communis. 
Ps. tumidus, Schneider,* in the alveoli of the lung of Phoccena 
communis. 
Ps. convolutus , Kuhn,* in the bronchi and pulmonary vessels of 
Phoccena communis and Globiocephalus svineval. 
Ps. ovis pulmonalis, Koch,f in the bronchi of the sheep. 
In Ps. minor , tumidus , and injlexus the spicula are short and leaf- 
like, occupying only of the entire length of the animal. In Ps. 
alatus , convolutus , and ovis pulmonalis they measure about of the 
length of the body. The habitat of Ps. ovis pulmonalis is very dif- 
ferent from that of Ps. alatus and convolutus , while the two last- 
named species are distinguished among other things by the fact that 
on the tail end of the body in the male of Ps. convolutus the bursa 
touches the round terminal lappets, | and exhibits striking curved 
lines ; but in Ps. alatus the bursa is separate from the terminal 
lappets, and forms no such lines. Furthermore, the cuticle of Ps. 
convolutus is covered with longitudinal markings, which are absent 
in Ps. alatus ; and again, Ps. convolutus measures 40-50 mm., and 
Ps. alatus 16-17 mm. in length. 
Explanation of Plate. 
Fig. 1. Head end. 
Fig. 2. Terminal lobes of the tail end of the male, seen from the 
ventral surface. 
Fig. 3. The same, seen from the left side. 
Fig. 4. Posterior end of the male, seen from the ventral surface, less 
magnified than figs. 2 and 3. a , muscles of the bursa. 
Fig. 5. Posterior end of the female, seen from the ventral surface, a , 
vulva ; &, anus. 
Fig. 6. The same, seen from the right side, a , vulva ; b, anus. 
* v. Linstow, Compendium der Helminthologie , Hannover, 1878, p. 59. 
+ A. Koch, “Die Nematoden der Schaflunge,” Oester. Monatschr. f. Thier- 
heilkunde , Wien, 1883, pp. 9-19. 
+ Schneider, Monographic der Nematoden , p. 174, pi. xii. fig. 3. 
VOL. XVI. 27/12/88 
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