CRUSTACEA. 
613 
appearance at the same time as the mandibles, and in the form 
of simple cellular protuberances. The cuticula belonging to the 
stage of Nauplius is developed at the same time on the whole 
surface of the embryo, and it is its first cuticula, there being no 
blastodermic mould. The tail, which is bifid in Mj/sis vulgaris 
(Thomps.) and chamaleon (Bell), is simple, and terminates in a 
blind sack in Mysis ferruginea. Finally there is formed on the 
sides of the embryo an organ which has the same morphological 
value as the foliaceous appendages of Asellus aquaticus. Bull. 
Acad. Roy. Belg. xxviii. pp. 232-249, with a plate. 
Mym mixta (Lilljeborg), perhaps (Kroyer), and M. neglecta, sp. n., 
Christianiafjord, described by G. O. Sars, Undersbg. Christ, dybvandsf. pp. 
S5-37. 
Afym incrmis (Rathko), spiritus (Norman), and armata (Sars), observed 
at the Shetland Islands, described by Norman, Rep. Brit. Associat. for 1808, 
pp. 200, 207. 
Mysidopsis? hispida, sp. n., Norman, ibid. p. 207, Shetland Islands. 
MysideiSf g. n. Abdominal feet of the male as in the preceding, man- 
dibles unequally armed, second maxillse with only two lobi incisivi. Type, 
Mysis insignis (Sars), Chrisianiafjord, Sars, Undersog. Christ, dybvandsf. 
pp. 28, 29. 
Leptomysis, g. n. Abdominal feet of the male as in the two preceding 
genera. Body very slender and nearly uncoloured. Type Mysis gracilis 
(Sars) ; a second species is M. lingmra (Sars). Sars, /. c. p. 29. 
GastrosaccuSf gen. nov., for Mysis sancta (Beneden), Norman, Rep. Brit. 
Assoc, for 1808, p. 208, Shetland. 
Boreomysis, gen. nov. All the abdominal feet (pereiopods) in the male 
strongly developed, two-branched, natatory. Auditory organ rudimentary. 
Type Mysis arctica (Kroyer), Christianiafjord, in 200 fathoms, and Greenland j 
another species,*^, tridens, sp. n., Lofoten Islands. This genus appears to be 
littoral in the Arctic seas, and to belong to the deep-sea fauna in Southern 
Scandinavia. Sars, 1. c. pp. 20-28. 
Hemimysis, gen. nov. Abdominal feet as in the preceding genera, other- 
wise next to the true Mysis ; abdomen attenuated and depressed behind. Jl. 
ahyssicola, sp. n., Christianiafjord, 160-200 fathoms, and Lofoten Islands, 260 
fathoms. G. 0. Sars, I c. pp. 32-34. 
Erythrops, G. O. Sars, new name for Nematopus of the same author, which 
is preoccupied j E. ahyssorum, sp. n., Christianiafjord, 200-230 fathoms, and 
Lofoten Islands in northern Norway, 300 fathoms. G. 0. Sars, 1. c. pp. 21-23. 
Nematopus serratus (G. 0. Sars) described by Norman, ibid. p. 208, found 
at the Shetland Islands. 
Parcrythrops, gen. nov., distinguished from Erythrops by the very short 
and stout shape of the body. Typo Nematopus ohesus (Sars), G. 0. Sars, 1. c. 
p. 24. 
Amhlyopsisj gen. nov. [preoccupied for the subterranean fish from Ken- 
tucky]. Oculi rudimentarii singulari modo in laminas duas subtriangulares 
intus contiguas non vero coalitas transformati, in medio pigmento rubro dif- 
fiiso, nullis vero lentibus vel aliis in oculis compositis demonstratis parti bus 
