3 5h PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 



'*"hryxuE abdomiiialis Lilljeborg, Ofversigt af Kongl. Vetenskaps Akademiens 

 Forh. Stockholm, 1852, p. 11. — Bopyrus ahdominalis Kroyer, Naturhist. Tidssk. , 

 Bind iii, p. 102, 289, pi. 1, 2, (1840); Galmard's Voyage en Scandinavie, etc., 

 Atlas, pi. xxix, fig. 1 a-u, "1849." 



Parasitic on Pandalus, Hippolyte, etc., and found as far south as 

 Massachusetts Bay. 



Dajus mysidis Kroyer, Gaimard's Voyage en Scandinavie, etc.. Atlas, pi. xxviii, 

 fig. 1, "1849." — Bopyrus mysidum Packard, Mera. Soc. Nat. Hist. Boston, 

 vol. 1, p. 295, pi. viii, fig. 5, 1867. 



Parasitic on Mysis, but not hitherto found south of Labrador. 



Jaera albifrons Lcacb, Edinburgh Encyclopaedia, vol. vii, p. 434, "1813-14"; Trans. 

 Linn. Soc. Loudon, vol. xi, p. 373, 1815. — Jcpra copiosa Stimpson, Mar. 

 Invert. Grand Manan, p. 40, pi. iii, fig. 29, 1853. 



Common throughout the New England coast under sea-weed, in tide 

 pools, etc. A comparison of specimens received from Oban, Scotland^ 

 through the kindness of Eev. A. M, Norman, indicates that our species 

 must be regarded as identical with the well-known British species, and 

 is therefore common to the two coasts. 



Janira a]Xa. = Ascll odes alta Stimpson, Mar. Invert. Grand Manan, p. 41, pi. iii, fig. 

 30, 1853. 



A northern species not as yet found south of Massachusetts Bay, oc- 

 casionally collected in tide-pools, but usually dredged, and extending to 

 a depth of 190 fathoms. 



This species is easily distinguished specifically from J. maculosa Leach, 

 the type of the genus, but does not appear to differ by characters of 

 generic importance, and I have therefore referred it to the older genus. 



Janira spinosa, n. sp. 



A second species of this genus was obtained in the summer of 1878, 

 and on examination it appears to be as yet undescribed, although some- 

 what resembling J. lacmiata G. O. Sars, but distinguished by the double 

 instead of single row of spines along the dorsal region of the thorax. 



The head is strongly rostrate, and has the antero-lateral angles acutely 

 produced, but shorter than the median rostrum. The eyes are small 

 and black, and placed a little behind the middle of the head, at about 

 an equal distance from the median line and the lateral margin. The 

 antennulfB are slender, and slightly surpass the first four segments of the 

 antennoe. The antennse are about as long as the head and thorax 

 together, and the scale attached to the second peduncular segment is 

 slender and pointed, surpassing the third segment. The flagellum forms 

 about half the length of the antenna, and is slender, tapering, and multi- 

 articulate. 



The thoracic segments are all acutely produced at the sides into one 

 or two salient angles, forming a row of acute serrations along the sides 

 of the body. The first segment has a single angle produced somewhat 



