28 



0.55 mm. in length; and further the figures of the animal given by that author 

 and by Th. Scott do not fully agree with the form examined by me. Finally, 



N 



on comparing my drawings with those given by the above-named authors, I also 

 find some differences in the structural details. 



Occurrence. I have found this form occasionally in the upper part of the 

 Christiania Fjord in depths of about 16 fathoms, muddy bottom. The specimen 

 examined by Boeck was likewise from that locality. 



Distribution. ? British Isles (Brady, Scott). 



Fam. 4. Ectinosomidae. 



Characters. -Body of a peculiarly smooth appearance, and more or lesa 

 fusiform in shape, with no very conspicuous demarcation between the anterior and 

 posterior divisions. Cephalosome wholly confluent with the 1st pedigerous segment, 

 and produced in front to a more or less prominent rostral plate continuous with 

 the cephalic shield. Epimeral plates of the 3 succeeding segments well developed. 

 Last segment of metasome without such plates. Urosome consisting in female of 

 4, in male of 5 segments, the last one generally small and more or less cleft at 

 the end. Caudal rami discontiguous, divergent, with the 2 middle apical setae 

 more or less elongated. No true eye present. Anterior antennae comparatively 

 small, and composed of a limited number of articulations. Posterior antennae 

 with strong denticulated spines at the tip, outer ramus slender, 2- or 3-articulate. 

 Oral parts differing rather greatly in their structure from those in the preceding 

 families. Natatory legs powerfully developed, with both rami 3-articulate and 

 densely spinous. Last pair of legs lamellar and edged with strong spiniform setae. 

 Ovisac single. 



Remarks. This family, the type of which is the genus Ectinosoma of Boeck, 

 exhibits several well-marked differences from the preceding ones, both as regards 

 the external appearance and the structural details; and as there are several genera 

 which so far closely agree with each other, the establishment of this new family 

 may be fully justified. It comprises as yet 4 genera, all of which are represented 

 in the fauna of Norway. 



