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I think the best plan is to begin by giving an account of the features which are 
common to all species, subsequently describing each species separately. A tuft of hairs 
outside the base of the maxillule in both sexes, and the shape of the frontal border in the 
male, are probably the most characteristic features which distinguish them from all other 
species of the genus Spheronella. 
FEMALE. Body ovate or sub-globular, with well-defined head. Antennule of 
about medium length, 3-jointed, the last joint provided with rather short sete. Frontal 
margin naked. Antennz rudimentary (pl. III, fig. 2¢,c¢), but generally visible. The mouth 
of middle size. Sete of the mouth-border of medium length. Mavxillule provided with an 
additional branch; outside and somewhat behind their base a peculiar, pretty large tuft of 
hairs turning outward. Mavxille of medium size. Maxillipeds normal, with hairy spots on 
their basal joint. The sub-median skeleton between the rostrum and the base of the maxilli- 
peds forms rather broad longitudinal plates, but there is no transverse list on the ventral 
side at the posterior limit of the head. The lateral margin of the head provided with a 
row or a stripe of moderately long hairs. Trunk-legs and caudal stylets always distinct 
(e. g. pl. II, fig. 6a). Genital area much narrower than the head, broader than long, plate- 
like or only with a solid ring which has no opening in front. The curved genital apertures 
turn their front extremity forward, their hind extremity sideways, and their distance from 
each other is shorter than the length of each. Caudal stylets either on the posterior margin 
of the genital area (pl. II, fig. 5b) or, as a rule, behind or far behind it (pl. LU, fig. 3). 
MALE. This sex is known of six of the species. The body is from one third to 
one half longer than broad. The head about the size of the trunk. The frontal border 
produced so as to form in advance of each antennula a pretty large, rounded, distally ciliated 
lobe, which is separated by a deep and broad incision from the odd, long, broad and almost 
square median plate, the sides of which are often somewhat diverging, sometimes parallel; 
its slightly curved anterior margin, as well as the distal part of the lateral margin, are 
furnished with fine and short hairs. Antennule, antenne, rostrum, maxillule, the hair-tuft 
at their basis, maxillee and maxillipeds, chiefly as in the female. The sub-median skeleton 
with first and second pairs of processes well developed; first pair rather prominent, triangular, 
pointed, situated close in front of or overlapping the base of the maxillipeds; second pair 
situated at the inner angles of the maxillipeds, elongated, extending over the basal part of 
the trunk, and more or less diverging. Lateral margin of the head ciliated; from its posterior 
extremity a narrow belt of long hairs extends upward over the side and in an oblique 
direction across the back. The ventral surface, the sides and the hindmost part of the trunk 
are covered with moderately long, posteriorly towards the back with very long hairs, leaving 
a large naked area behind the above-mentioned transverse belt. The legs of moderate and 
sub-equal length; the first pair consist of a peduncle, one branch, and a short conical 
process on the outer side at the apex of the peduncle; the proximal part of the peduncle is 
stout and rather broad; the branch which must be homologous with the outer one in the following 
