139 
OVISACS. Of about equal size, elongated oval (fig. 2b); the specimen represented 
measures ‘71 mm. in length and -46 mm. in breadth. Eggs numerous, about middle-sized. 
Judging from the size of the ovisacs, the adult females of this species must be supposed to 
be 1mm., or somewhat more, in length. 
LARVA. A specimen found free (fig. 2f) is 16mm. long. Cephalothorax more than 
1/2 time longer than broad. The front with a long, almost straight list inside the base of 
the antennula. Antennule 3-jointed; olfactory seta about three times longer than the an- 
tennula and scarcely half the length of the cephalothorax. Antennz much as in the larva 
of S. intermedia. Of the maxillule only a single seta has been discovered. First joint of 
the maxille of a little more than medium length, smooth; the two others normal. Second 
joint of the maxillipeds shorter than the third. Abdomen small, its first segment somewhat 
longer and a trifle broader than the second, and its long seta reaching a little beyond the 
ends of the caudal stylets; second segment scarcely longer and not broader than the third, 
from which the relatively good-sized caudal stylets are well set off, but their long sete are 
defective in my two larve. 
POST-LARVAL DEVELOPMENT. A single pupa (fig. 2g) found on the glass 
during the preparation is ‘17mm. long and ‘11 mm. broad; it is described above on p. 60. 
HABITAT. Ampelisca tenwicornis Lilljbg. from Denmark. I have found the 
parasite on nine specimens, six of which were rather young, without marsupium. On each 
of five of these occurred a not half-grown or very small female (in one case it was evidently 
just hatched); on the sixth specimen I found two free larve. In a specimen with half- 
developed marsupium occurred one not half-grown female. The two other hosts were females 
with fully developed marsupium; in one of them occurred five ovisacs, in the other the above- 
mentioned flattened female and four of the host’s own eggs. 
REMARKS. By the very long sete of the trunk-legs this species is easily di- 
stinguished from all other hitherto known species of this genus. 
22. Spheronella Amphilochi n. sp. 
(Pl. VIL, fig. 3a—3b). 
FEMALE. The only specimen found was adult and measured 54mm. in length 
and ‘40mm. in breadth. The head (fig. 3a) is well defined from the trunk. The frontal 
margin with short and very fine hairs. Antennule tolerably long, with pretty long sete. 
Antenne 3-jointed, the basal joint appears shorter than the following joints; the terminal 
seta about the length of the last joint. Mouth-border of about medium breadth. Maxillulee 
with rather short additional branch. Basal joint of the maxillaze smooth. Basal joint of the 
maxillipeds long, slender and naked, second and third joints coalescent, last joint ending in 
a point. Sub-median skeleton naked, but a peculiar characteristic in this species is that the 
18* 
