74 



mentary stars, arranged in transversal rows on the segments, and partly con- 

 fluent. Length of adult animal 7 mm. 



Remarks. — As pointed out by v. Beneden, this form was recorded by 

 Slabber as early as in the year 1778, under the Dutch name "Agaat-Pissebet", and 

 the specific name agata applied to this form by v. Beneden should therefore per- 

 haps be preferred to that proposed by Leach (pulchra); but the Leachian name 

 has been so generallyd used, that it would be inappropriate to change it. The 

 form recorded by the present author as Slabberina agilis, is undoubtedly the same 

 species, and I also fully agree with Dr. Hansen in regarding the Slabberina gra- 

 cilis of Bovallius as only founded on a young specimen of the present species. 



Occurrence. — I have observed this form rather plentifully in the inner 

 part of the Trondhjem Fjord, at Levanger, where it occurred close to the shore 

 in quite shallow water, swimming rapidly about between the stones in a manner 

 very similar to that observed in the Dytisci and Gyrini. I have also taken it 

 near the sandy beach of Listeiland, and occasionally in the Christiania Fjord, 

 at Laurkullen and Fredriksvsern. According to Dr. Bovallius, the specimen de- 

 scribed by him as Slabberina gracilis, was taken up in the dredge at Drobak from a 

 depth of 100 fathoms; but it is most probable, as opined by Dr. Hansen, that it 

 did not come from this depth, but had entered the dredge during its uphauling. 



Distribution. — British Isles (Leach), Kattegat (Meinert), Baltic at Kiel 

 (Moebius), Dutch coast (v. Beneden), coast of France (Bonnier). 



Fam. 5. Limnoriidae. 



• 



Characters. — Body subdepressed, capable of being rolled into a ball. Ce- 

 phalon short and very convex. Coxal plates behind the 1st segment of mesosome 

 well defined, laminar. Metasome composed of 6 well-defined segments, the last of 

 which is very large, clypeiform. Antenna 3 small, subequal in size. Oral parts on 

 the whole normal, adapted for biting. Legs of uniform structure, all being am- 

 bulatory in character. Pleopoda well developed, serving both for swimming and 

 breathing; 1st pair of same structure as the succeeding ones; 2nd pair in male 

 with a lateral stylet on the inner plate. Uropoda comparatively small, lateral, 

 rami not lamelliform. 



Remarks. — This family, first established by 0. Harger, is not difficult 

 to distinguish from any of the preceding ones, whereas in certain points it 



