MONOGRAPH OF THE EXISTING CKINOIDS. 629 



PERICLIMENES (LAOMENES) CORNUTUS BORRADAILE. 



This form was described from specimens collected by Prof. J. Stanley Gardi- 

 ner and Mr. Borradaile at Male Atoll, Maldives, and found on an undetermined 

 comatulid, which was red and brown in color. 



PERTCLIMENES (LAOMENES) CERATOPHTHALMUS BORRADAILE. 



Like the preceding, this species was found by Professor Gardiner and Mr. 

 Borradaile on a comatulid at Male Atoll, Maldives. 



PERICLIMENES (CUAPETES) BROCKETTI BORRADAILE. 



Professor Gardiner and Mr. Borradaile found this species at Male Atoll, 

 Maldives, living on a brown comatulid. 



PERICLIMENES (CUAPETES) POTTSI BORRADAILE. 



The originals of this species were collected at Torres Strait by Lieutenant Potts, 

 who found them living on Comanthus. Potts did not in life distinguish this form 

 from P. commensalis, so that probably the following remarks apply to both. 



He notes that this shrimp is comparatively common on the comatulids from 

 the Murray Island reef, but only one or two specimens were obtained at Mabuiag. 

 It is a very transparent creature, and though the general coloration, a beautiful 

 purple, harmonizes with the host, there is no distinct arrangement in longitudinal 

 stripes. The low power of the microscope shows that there is a blue pigment con- 

 tained in very numerous small cells which are regularly disposed over the body; 

 also evenly distributed, but much fewer in number, are cells containing red pig- 

 ment, which may be spherical or branching. The gut is colored red. The general 

 effect thus is purple. 



PONTONIOPSIS COMANTHI BORRADAILE. 

 Fig. 944, p. 621. 



Lieutenant Potts, who collected the specimens described by Borradaile, says 

 that this species was found only at Mabuiag on the light-colored varieties of 

 Comanthus annulatus, in which a great deal of green pigment had developed. In 

 general this small crustacean (it is about 8 mm. long) exhibits a striking corre- 

 spondence with its host. Alternate longitudinal stripes of bright green and black 

 or dark brown occur on the dorsum, and these match the crinoid pinnules, in which 

 green and yellow alternate with dark green or black. There also occurs another 

 variety, in which the green pigment is replaced by yellow and the darker pigment 

 by red or brown. In the specimen figured by Potts, which he states is typical of 

 the species, there were three yellow stripes alternating with two brown stripes of 

 equal width ; the chela was yellow, with a brown line. In this case, however, the 

 commensal, living on a crinoid in which green predominated, was very conspicuous, 

 and Potts supposes that it had developed its pigment in association with another 

 individual of a different color type. 



