159 



Remarks. — This form was first described by Cuvier in the year 1792 as 

 Oniscus hypnorum, and by subsequent authors was referred to the genus Ligia, 

 until Brandt established for it a distinct genus; but the original specific name 

 was changed by that author, as also by most subsequent zoologists, excepting 

 Mr. Budde-Lund, who again restored the Cuvierian name. It is an easily recogniz- 

 able form, being particularly distinguished by the peculiar structure of the uropoda. 

 From its nearest ally among the northern Oniscoida, Ligia oceanica, it is more- 

 over easily distinguishable by the abruptly contracted metasome and the feebler 

 development of the antennae. 



Occurrence. — In Norway this form has not yet been met with ; but I re- 

 gard it as highly probable, that, on a closer investigation, it will in reality be 

 found to occur somewhere in the country, since it is not uncommon either in 

 Sweden or Denmark. The figures here given are from Danish specimens kindly 

 sent to me from the Museum of Copenhagen. According to Mr. Budde-Lund, it 

 is found in very moist situations. 



Distribution. — Sweden, Denmark, Germany, France, Britain, Turkey. 



Fam. 2. Trichoniscidae. 



Characters. — Body more or less elongated, with the lateral parts of the 

 segments, as a rule, not much expanded. Cephalon with distinct, though not 

 very large lateral lobes, front more or less produced, but scarcely marginate. 

 Metasome generally much narrower than the mesosome, last segment forming at 

 the end a thin projecting plate. Eyes small or wholly wanting. Antennulae mi- 

 nute, but having the terminal joint well developed and tipped with a number of 

 delicate sensory filaments. Antenna? not much elongated, and minutely spinulose 

 throughout, flagellum composed of only a restricted number of articulations, which 

 are less distinctly defined than in the Ligiidm, the last one terminating in a 

 bunch of delicate hair-like bristles. Buccal mass very prominent below. Man- 

 dibles with the molar expansion well developed, penicils very few in number. 

 Anterior maxillae with the masticatory lobes narrow and produced, the inner one 

 with 3 hairy bristles at the tip. Posterior maxillae without any penicils inside. 

 Maxillipeds with the terminal part generally imperfectly articulated, masticatory 

 lobe terminating in a thin lash, epignath narrow Unguiform. Legs not much 

 elongated, coarsely spinous, dactylus simple. Opercular plates of pleopoda very 



