of Edinburgh, Session 1879-80, 
711 
2. On Some N ew Crustacea from the Cementstone Group of the 
Calciferous Sandstone Series of Eskdale and Liddesdale. 
By B. NT. Peach, F.G.S., of the Geological Survey of 
Scotland. Communicated by Professor Geikie. 
(Abstract.) 
The species enumerated in this paper belong to the two orders 
Phillopoda and Decapoda. 
Of the Phyllopods, the author describes two species of Ceratiocaris 
(Salter), which differ from their Upper Silurian allies in the enor- 
mously-developed abdomen and in the small size of the carapace, 
also in the comparative insignificance of the side spines of the tail 
compared with the telson. As far as the author is aware, these are 
the first obtained from the Calciferous Sandstone series, although 
carapaces of Ceratiocaris have been got from the Mountain Lime- 
stone of England. (C. Scorpioides , 1 \ to 2 inches long; C. elongatus , 
5 to 8 inches long.) 
Of the Decapods, seven new species are described, viz., five 
belonging to the genus Anthrapalcemon (Salter), one belonging to 
the genus Palceocrangon (Salter). These do not differ in any 
essential respect from the recent Macrurous Decapods, and one 
belonging to Paloeocaris (Meek and Worthen) — a genus which, as 
far as the author is aware, has hitherto only been got from the 
Blinois Coalfield, in the United States, and is represented by only 
oue species, the Paloeocaris typus (Meek and Worthen). He pro 
poses to call the present one P. Scoticus. This is a most interesting 
creature, for the carapace extends only over the cephalic region, 
while the thoracic segments are all free and movable, yet its cephalic 
appendages and the character of the tail show it to be most nearly 
allied to the Macrurous Decapods. 
3. Gaseous Spectra in Vacuum Tubes. 
By Piazzi Smyth, F.B.S.E., &c. 
(Abstract.) 
The work described in this paper consists of rather careful 
measurements, but under low dispersion only, of the spectra of 
twenty gas-vacuum tubes, generally of different gases and illuminated 
4 Q 
VOL. X. 
