HORN EXPEDITION—CRUSTACEA. 
239 
union between the two halves of the carapace extending along the whole length of 
the dorsal line, which is raised into a much-compressed spined keel. Lines of 
growth ten to fifteen clearly-marked, thread-like ridges ; the intervals between tlie 
more recent lines of growth continued on the dorsal keel into backwardly-directed 
spines, the posterior edges of which are formed by the lines of growth. Spines 
decreasing in size from behind forwards. Beaks well marked. First pair of 
antenme much smaller than the second. Number of feet, twenty-six to thirty-two 
pairs. Haft-organ present. 
This genus may be distinguished from Estheria by the presence of a haft- 
organ ; from Limnadia and Evlinmadia by the spinous processes on the dorsal 
edge of the caiapace, by the difierent number of lines of growtli and of pairs of 
feet; from Livmadella by the difference in size of the two pairs of antenna\ 
(6) Limnadopsis squirei, sp. n. (Figs. 15, 16, 17, 18, 19). 
Carapace ovate, much compressed. Dorsal margin marked off from the 
anterior margin by a distinct angle, and from the posterior margin by a pi'ominent 
spine, into which the latter is continued. Dorsal margin from anterior angle to 
umbo straight, sloping upwards and backwards ; from the umbo it rises more or 
less abruptly, then falling gradually towards the posterior and usually rising 
slightly near its termination. A varying number (one to twelve) of backwardly- 
directed serrations correspond to the intervals between the lines of growth. 
Anterior, inferior and posterior margins forming a fairly regular ellipsoidal curve. 
Lines of growth forming thin, ridge-like elevations, eleven to fifteen in number. 
Interspaces between the lines of growth very minutely punctate, the punctations 
being only visible with a power as high as a Zeiss A. 
Size op Spirit Specimens. 
Male. 
Empty 
Female 
shell.' 
with ova. 
Length 
23-5 mm. 
27 mm. 
.. 22-5 mm. 
Height 
- 16 „ , 
... 20 „ . 
.. 16 „ 
Tliickness through both valves 
4 „ 
... 5 „ , 
5 „ 
The whole body of the animal is contained within the carapace, to which the 
animal is attached in the region of the umbones and by the adductor muscles. 
Head bluntly rounded. Haft-organ present; eye more conspicuously stalked 
in male than in female ; rostrum shorter and blunter in female than in the male. 
