181 



13. Ampelisca pusilla, G. 0. Sars, n. sp. 



(I'l. 03, lig. 2). 



Form of liody somewhat sliorter and stouter than in the last species. 

 (V]ili;ih)n comparatively short, and but little tapering antei'iorly, front obliquely 

 I'marginated, with the lower corner Imt little projecting. First pair of coxal 

 plates less ol)liquely expanded, and, as in the 2 preceding species, not con- 

 cealing the basal part of the inferior antennae; 4th pair greater in depth tiian in 

 breadth, with the inferior edge shorter than the ])osterior. Last pair of epimeral 

 plates of metasome not produced at the lateral corners, and nearly rectangular. 

 Fii'st segment of urosome with the dorsal carina in female nearly obsolete, 

 in male more distinct, and bounded anteriorly by a deep saddle-shaped depres- 

 sion. Eyes, as in A. amhJjiops, imperfectly developed, without any trace of 

 corneal lenses. Antennse in female nearly equal-sized, densely setous, and but 

 little exceeding half the length of the liody, in male more unequal, the 

 inferior ones being considerably more elongated than the superior. Anterior 

 gnathcqioda somewhat coarser in structure than the posterior, with the pro- 

 l)odos oval, and fully as long as the carpus. The 4 anterior pairs of pereio- 

 ])oda about as in A. amhlyops. Last pair of pereiopoda with the basal joint but 

 little longer than the remaining part of the leg, posterior expansion rather 

 broad, and obtusely truncated at the tip, outer part of the leg nearly as in 

 A. amhhjops, except that the propodal joint is somewhat larger. Same legs in 

 male somewhat smaller, with the basal joint less expanded, and more obliquely 

 truncated posteriorly. Last pair of uropoda comparatively smaller than in 

 the said species, with the rami not nearly so broad. Telson without any 

 dorsal denticles, but with 2 small marginal spinules near the tip on each side. 

 Body whitish, pellucid, without any distinct colouring, except for a faint 

 rosy tinge on the anterior part of the body, at the sides of the 1st pair of 

 coxal plates. Length of adult female scarcely exceeding 5 mm. 



EemarJis. — This is by far the smallest of the indigenous Ampeliscse, 

 and tliough nearly allied to A. anihJyops, readily distinguished by the com- 

 ))aratively shorter and equal-sized antennse, as also by the form of the cepha- 

 lon, by the non-produced last pair of epimeral plates of metasome, and by 

 the much slighter dorsal cai'ina of the 1st segment of urosome. 



Occurrence. — I have found this diminutive species rather abundantly 

 in several places, both off the south and west coasts of Norway, and northwards 

 to Selsovig, lying exactly at the polar circle. It only occurs in considerable 

 de])tlis, from 100 to 200 fathoms, muddy bottom. 



Dhtrihution. — Bohuslan (Stockholm Museum). 



