70 H. J. HANSEN. 
especially marine animals of various orders and classes ; of 
Spheromide I gathered a large number of specimens, most 
of them belonging to the genera Spheroma (Bosc) and 
Cymodoce (Leach). In attempting to name the material 
of Cymodoce, I soon felt that the first thing to be done was 
to separate the adult males, which proved to belong to three 
species, then to refer immature males and the females to their 
respective adult males. The literature could not help me, 
but, fortunately, the number of specimens of nearly all stages 
of all species was so rich that the task could be carried through. 
During this examination I observed that the adult females 
had neither eggs nor young in the marsupium, but that the 
brood could be discerned through the skin of the ventral sur- 
face of the thorax; the young occupied internal pouches, as 
had been shown by Leichmann to be the case in Spheroma 
rugicauda (Leach). Furthermore, I observed that in the 
same adult females of Cymodoce the proximal half of the 
maxillipeds is strongly expanded, forming large ciliated plates 
not found in immature specimens or males, and that the end 
of the mandibles is light-coloured, while it is dark-brown or 
black in other specimens; a subsequent dissection showed 
that the three anterior pairs of mouth-limbs and the 
distal half of the maxillipeds in egg-bearing specimens of 
Cymodoce have been so strongly reduced that the animals 
cannot eat, while the proximal half of the maxillipeds has 
been exceedingly expanded; in Sphzroma the mouth-parts 
are similar in both sexes and in young animals. 
These facts and other features were discovered ten years ago, 
but a publication was postponed. During a stay in London in 
1902 I looked through the large collection of Spheeromide 
in the British Museum, wrote numerous notes, and figured 
some details; most of the specimens examined being types or 
co-types for species established by Leach, Say, White, Miers, 
and Haswell, this perusal has been of great importance for 
my study. The next year I began to work out a revision of 
the genera of Spheromide. The U.S. National Museum, 
and especially Dr. Chas. Chilton in New Zealand, favoured 
