198 DUBLIN UNIVERSITY 



Colour : deep chocolate brown black, with lighter patches. 



Locality : Jamaica. 



The specimen in the British Museum, the only one I have seen, 

 wants the external antennae ; but from the fragments of those that re- 

 main, and other characters, an affinity can be traced between this 

 genus and the Porcellionidae. See remarks on Deto, infra. 



The form of the telson is unique; the posterior pleopods show an 

 approximation to Deto ? but in the absence of the antennae it is impos- 

 sible to speak positively. 



Family.— PORCELLIONID^. 

 Genus. — Ourachjertts {A. White, " Brit. Hus. Cat," p. 100.) 

 Body flattened; head transverse; lateral and frontal lobes well 

 developed. Internal antennae three-jointed. External antennae : pe- 

 duncle five- jointed; tige two-jointed, conical. Cephalothorax : coxae 

 well developed. Abdomen: coxae, first and second somite obsolete; 

 third to fifth, narrow, curved, and long. Telson : coxae obsolete. Pos- 

 terior pleopods : peduncle quadrilateral. Accessory lobe extremely 

 minute, arising from posterior margin of peduncle. Accessory filament 

 minute, subtrigonal. Ischium long, flattened, and spathulate. Species, 

 0. caudatm. 



Ourachcerus caudatm. (A. White.) 



Body oval, shining, covered with smooth granules. Head trans- 

 verse, faintly tuberculated. External antennae : peduncle longitudi- 

 nally sculptured ; first articulation, short ; second, broader, its margins 

 produced, and angular ; third, same length as second, but somewhat 

 narrowed ; fourth, three times length of second, its upper margin fur- 

 nished with a moderate-sized tooth ; fifth, twice length of fourth, 

 slender and narrow. Tige two-jointed ; basal articulation, four times 

 length of terminal, which is conical. 



Telson triangular, acuminate. Posterior pleopods as genus. Acces- 

 sory filament barely attaining to apex of peduncle. Ischium lamellar,* 

 spoon-shaped, flattened, nearly six times as long as peduncle. 



Locality unknown. 



The general outline and appearance of the surface of the body of 

 this strange species closely resembles Oniscus murarius, as well as the 

 form and development of the coxae and telson. The characters of the 



