32 



orifices are shown only in some of the ilhistrations of the genital i-egion, and they are 

 often very difficult to find, if one or each of them has not a spermatophore attached to it; 

 this, however, is rather frequently the case; sometimes we find even two spermatophores, or 

 at least their stalks, on each orifice (pi. XIII, fig. 1 e). Such a spermatophore is a globular 

 or ovate vesicle with a stalk twice or three times as long as itself; this stalk — a thin 

 tube — is attached to the skin closing on the above-mentioned orifice, or sometimes — by 

 mistake — outside it (pi. IV, fig. 2c, where we find one spermatophore on each orifice and 

 the stalk of a tliird one outside it). The two receptacula, when filled, have a strong 

 refraction of light, which as a rule makes them easy to find. Their outlines are traced with 

 dotted lines in some of the illustrations. — In Splurr. Munno}}sidis I have found in the an- 

 terior part of the plate two holes (pi. X, fig. 4c, k) corresponding to those in Mytiidion 

 abyssorum and Aspidoecia (see p. 34— 35). 



In the species wliich have trunk-legs there is always a pair of caudal sfylefs shaped 

 somewhat like the legs. In Homoeoscelis (pi. II and pi. XIII) they are a little thicker and 

 longer than the legs; in Spluprondla and Choniostoma they consist either of a cylindrical, a 

 rounded or a triangular joint terminating in two or three setae (which rather frequently fall 

 off dui-ing the preparation); they are sometimes longer, sometimes shorter than the setae of 

 the legs (as e.g. pi. VII, fig. 2e). In Sphceronella Acanthosonis each caudal stylet has (me 

 single rather long seta (pi. VII, fig. 5d). In Sphcer. modesfa, which has no trunk-legs, each 

 stylet consists of a rather short, thick joint, from the innei' posterior angle of which proceeds 

 an acute »joint« twice as long but scarcely half as thick, which must be considered as a trans- 

 formed seta, and outside it are seen one or two simple setae (pi. IX, fig. 2e). Nearly all the 

 other species which lack trunk-legs are devoid of caudal stylets as well. The place of these 

 stylets varies much; in most species they are situated close together, either on the plate or 

 the ring , a little behind the genital apertures , or close behind the posterior mai-gin of the 

 ring or plate, but in the species belonging to the group of Spliferonella Leud-artii they are 

 situated pretty far or very far from each other, and also more or less far behind the genital 

 area (pi. II, fig. 2e and fig. 3 b). 



The remarkable fixation oi Sphceronella paradoxa will be described in the systematic 

 part; here it may be sufficient to draw attention to it. 



II. Stenothochercs (pi. I). This genus, comprising two species, deviates considerably from 

 the tlu-ee recently mentioned genera, and in at least two important features: — lai-ger trunk-legs 

 with two branches and a separate abdomen — it comes nearer to the less transformed Copepoda. 



The body is sub-ovate or nearly globular; its abdomen is comparatively rather small 

 and prominent posteriorly on the ventral side or on the hind margin itself. It has no separate 

 head, not even the vestige of a fi-ame (like the one in Choniostoma). The sub-median skeleton 

 is reduced to a plate in front of each maxilliped (pi. I, fig. le, h and fig. 2f), and this plate 

 may extend forward like a list between the maxillae and the outside of the rostrum. An- 

 tennulae, antennae, rostrum, maxillae and maxillipeds occupy a larger space on the ventral 



