20 Bulletin American Museum of Natural History [Vol. LIII 
“During the low, equinoctial tides I had a splendid opportunity 
of investigating the many dark brown and greenish knolls scattered over 
the bottom of the bay of St. Paul de Loanda. So uniform is their 
appearance that they might be taken for moss-covered stones, though 
actually they represent a great variety of associations of sponges, 
ascidians, mollusks, and other invertebrates. Seldom more than a foot 
in diameter, these bunches are nearly flat below and lie loose on the 
eround. An interesting exception is when they are formed about the 
upper fifth, or protruding portion, of the large razor shells Pznna rudis 
Linneus, which thus are completely concealed. The Pinna is of course 
anchored in the sand by its long silk-like byssus but can be removed by 
placing one’s hands on either side beneath such bunches and pulling 
slowly. After removing the various sponges, the shell can be easily 
opened by inserting a knife in it. Covered by the mantle, and well con- 
cealed inside the Pinna, Athanas grimaldii lives as one of its commensals. 
Often it is necessary to turn the shell upside down and shake it vigorously 
to make the Athanas drop out. In small specimens of Pinna only one 
was found, in larger ones mostly two, but in several three. To this 
symbiotic community belong also Pontonia tyrrhena and Crangon of an 
undetermined species. When placed in alcohol these decapods shed their 
chelee and limbs to such an extent that I used separate vials for the speci- 
mens removed from any one shell. 
“Hiding in these bunches, among the caisent creatures or below 
them, are a number of crustaceans such as Palemon squiila Linneus (p. 
24), Pisa carinimana Miers,! Dromia atlantica Doflein,? and Pilumnus 
verrucostpes Stimpson.®”’ (H. L.) 
Crancon Weber 
Crangon WEBER, 1795, ‘Nomenclator entomologicus,’ p. 94 
Crangon langi, new species 
Text Figure 63 
Type Locatiry.—Banana, July 1915, 17¢", 299 (1 ovig.); August 1915, 37, 
792. (Amer. Mus. No. of type 4799.) ar 
. MEASUREMENTS.—The largest specimen is a female 54.5 mm. long from rostral 
point to end of telson. The figured male, holotype, is 34 mm. long from rostral point 
' to end of telson; carapace 11, abdomen and telson 23, telson 5, large chela 18.mm. 
long. 
eee nn SSeS SSS SSS SSS SSS sSNA 
1Lang, in Rathbun, 1921, Bull. Amer. Mus, Nat. Hist., XLIII, pp. 467-468. 
4Lang, loc. cit., p. 394. 
‘Rathbun, loc. ctt., p. 437. 
