630 BULLETIN 82, UNITED STATES NATIONAL MUSEUM. 



DECAPODA ANOMUKA. 



Family GALATHEID^E. 



In every large collection of comatulids received from the East Indian region 

 small galatheids, usually conspicuously striped longitudinally, are found asso- 

 ciated with some of the specimens. 



These commensal galatheids have recently been studied in the field by Lieut. 

 F. A. Potts. His observations did not lead him to suppose that the galatheids 

 occur in pairs on each host, as is usually the case in Synalpheus; but the absence 

 of evidence on this point may be due to the fact that they are inclined to leave the 

 host whenever disturbed. 



They are not by any means found so commonly on crinoids as are the species of 

 Synalpheus, though Galathea elegans is not infrequent. 



There is no special modification for clinging to the crinoids other than the 

 spines on the dactyli of the thoracic legs. 



The animals are thigmotropic, and after detachment immediately swim back 

 to the host. 



White, in 1847, listed without description the first of these commensal 

 galatheids to come to light, Galathea elegans, as among the crustaceans in the 

 collections of the British Museum. His specimens, brought home by the Samarang, 

 were from Corregidor, Luzon, and Unsang, Borneo. In the following year, in 

 the account of the voyage of the Samarang, Adam and White figured, but did not 

 describe, the species. 



In 1852 Prof. James D. Dana described a new species, G. longirostris, which 

 was found on a comatulid dredged at Fiji in 10 fathoms. 



In 1882 Prof. William A. Haswell described G. deflexifrons, basing his de- 

 scription on a specimen taken by the Alert in Albany Passage, Torres Strait, and 

 stating that it lives on comatulids. 



In 1884 Miers placed G. deftexifrons in the synonymy of G. elegans and 

 recorded, with annotations, various specimens of the latter taken by the Alert. 



Mr. T. Southwell in 1906 recorded three specimens of G. longirostris, with the 

 color markings well defined, which were found adhering to individuals of Ceno- 

 metra herdmani taken in the Gulf of Martaban, Ceylon, in shallow water, and 

 at a depth of 7 to 9 fathoms. 



In 1913 Dr. Heinrich Balss recorded G. longirostris from the Bonin Islands, 

 and doubtfully referred a single male from near Boschu, Sagami Bay, Japan, in 120 

 meters, to G. elegans. Of this latter he says that it apparently occurs on comatu- 

 lids. 



Lieutenant Potts has recently revised the species of galatheids commensal on 

 comatulids, of which he admits three, two of these described by himself from 

 material personally collected at Torres Strait. 



GALATHEA ELEGANS ADAM AND WHITE. 

 Fig. 942, p. 621. 



According to Potts G. longirostris of Dana and G. deftexifrons of Haswell are 

 synonyms of this species, which he described in detail, giving a revised diagnosis. 



