Arran Baryto-Sulphate Pigment. 139 
lucid: rostrum not so long as the first joint of the mandi- 
bles: thigh longer than the first tibial joint: auxiliary 
claws obsolete: abdomen produced and pointed. 
The body and legs are covered with spines. The segments 
of the body are elongated. The three coxal joints are equal ; 
the three tarsal joints minute. The body is nearly one line 
in length; the span of the legs two lines. 
Hab. Firth of Forth. 
Species 7. Nymphon spinosum (mihi). Rostrum longer than 
the palpi: posterior edges of the three middle segments 
of the body armed with a fringe of strong spines: first 
tarsal joint minute. 
The body is covered with punctures, except at the posterior 
edges of the three middle segments, which are armed with a 
fringe of strong thickset spines. The whole animal is stronger 
and coarser than any of the preceding species. The second 
coxal joint is longer than the first and third united; the first 
tarsal joint minute. The first joint of the oviferous legs is 
the longest. The abdomen is erect and prominent. 
Description of the Plate. 
Fig. 1. Phoxichilidium globosum. 
Fig. 2. Pallene circularis. 
Fig. 3. Nymphon spinosum. 
Fig. 4. Nymphon Johnstonii. 
Fig. 5. Nymphon pellucidum. ' 
Fig. 6. Nymphon minutum. 
Fig. 7. Pephredo capillata. 
Fig. 8. Rostrum and first segment of the body of N. spinosum, with 
the oviferous legs, palpi, and mandibles attached. 
Fig. 9. Same parts in Pephredo capillata. The circular body in the 
middle of the first segment appears to be connected with 
the organs of circulation. 
Account of the Arran Baryto-Sulphate Pigment. By Profes- 
sor Traiiu.* 
Axout two years ago I read a short notice of the Denbigh- 
shire manufacture of a pigment from Sulphate of Baryta. 
Since that I have visited the works lately erected in the isle 
of Arran by the Duke of Hamilton for the same purpose ; an 
account of which I beg leave to submit to the Society, pre- 
* Read before the Wer. Nat. Hist. Soc., 11th Dec. 1841. 
