5A 
(S. Argisse, S. longipes, 8S. microcephala and S. insignis), numerous pupe of Choniostoma 
mirabile, and three different stages of development of Mysidion commune. 
Let us begin with the simplest form of development. Ona completely adult female of 
Aspidoecia Normani, sitting on the dorsal surface of the abdomen of Evythrops serratus 
G. O. Sars, I found four larve attached (pl. XII, fig. 3b, where one of the larve is left 
out and two of the others designated by a v.) One of these came off easily, when touched, 
and it appeared that its skin had begun to burst along the lateral margin; on a closer 
examination it burst somewhat more, and it proved to contain a full-grown male. In this 
state the preparation is illustrated in pl. XII, fig. 3m. The spermatothece of the male 
were filled, and it had a very short and very thick frontal thread (s). This instance sutfi- 
ciently proves, that the male develops itself directly in the larva, without the intermediate pupa 
stage and without a second moult. IL also found a single larva, which had placed itself 
directly on the carapace of the host, but its examination gave no result, its development not 
being far enough advanced. However, I have found exceedingly small females sitting on 
different parts of the host, and I have not the slightest doubt that the larvee which are 
going to become females, attach themselves directly to the host, though I do not know, 
Whether they pass through the pupa stage or change directly into females, yet I feel 
inclined to accept the latter alternative, seeing that the parasite sits on the outside of its 
host, thereby running the risk of falling off very easily. 
We now come to a species in which both sexes pass through a pupa stage, namely 
Spher. Giardii (pl. VI, fig. 3i, fig. 3k and fig. 31). I have found three male pupz and 
not a few female ones. The body is of a short ovate shape; the males are more oblong and 
smaller, *125 mm. in length (fig. 3k), the female pupee stouter and varying in length between 
125 mm. and -142 mm. (fig. 31, which is drawn on the same scale of enlargement as fig. 3 k). 
In the female the foremost two thirds of the ventral surface form a broad, naked, odd area, 
whereas the whole remainder of the body is closely covered with rather short hairs. The 
male pupa is covered with hairs like the female, except that part of the back which corre- 
sponds to the head and the fipper parts of its lateral surfaces, which are naked (fig. 3k). 
Fig. 31 shows a male pupa from below, fig. 3k from the side; the antennule (a), the 
antenne (c), the maxillule, the maxilla, the maxillipeds, the trunk-legs and the caudal sty- 
lets are seen as naked, smooth, pouch-shaped processes, whereas the mouth is developed as in 
the adult animal; in front of the mouth we notice a semicircular, rather vaulted and prominent 
area, and between the maxilla and the maxillipeds two pairs of oblong, somewhat prominent 
knots, corresponding with the sub-median skeleton. The female pupa has also a free mouth 
and all the same processes and projecting parts as the male, from which, however, it is 
easily distinguished, not only by the above-mentioned difference in the extent of the hair- 
coat, but also by the size of the processes which stand in the place of the trunk-legs, and 
which are very small, whereas in the male pup these organs — especially the first pair 
— are much larger and furcate at the end This difference between the trunk legs, which 
