ISOPODS OF NORTH AMERICA. 637 



"Telson: coxse obsolete; posterior pleopoda (false feet) nearly 

 uncovered; peduncle (basis) somewhat triangular, broad; accessory 

 lobe badly marked; accessory appendage inserted nearly on same line 

 with ischium, flattened, rounded at the extremity; ischium long, sub- 

 ulate. Species, A. spiniger." KINAHAN." 



ACANTHONISCUS SPINIGER White. 



Acanthoniscus spiniger WHITE, List. Crust. Brit. Museum, 1847, p. 99. GOSSE, A 

 Naturalist's Sojourn in Jamaica, 1851, p. 65. KINAHAN, Proc. Dublin Uni- 

 versity, I, 1859, p. 197, pi. xix, fig. 4. BUDDE-LUND, Crust. Isop. Terrestria, 

 1885, pp. 241-242. RICHARDSON, Proc. U. S. Nat. Mus., XXIII, 1901, p. 569. 



Locality. Jamaica. 



"Body covered over with long spines arranged in a double longi- 

 tudinal row, one spine to each ring. In cephalothorax a second row 

 of shorter spines (two to each ring) on each side at junction of coxae 

 and body. 



"Head covered with coarse knobs; two minute spines behind; a 

 raised emarginate ridge marks out front. 



"Coxae of first cephalothoracic somite 

 expanded into a circular lobe; coxae of sec- 

 ond to sixth somite narrow; seventh some- , 

 what quadrilateral. 



" Abdominal somites: coxae, first and sec- 

 ond, obsolete; third, fourth, and fifth, nar- 

 row, curved, triangular. 



' k Telson cordato - pandurif orm : apex FIG - 68i. -ACANTHONISCUS SPINIGEK 



, ,11., -A' , ' (AFTER KINAHAN). a, TERMINAL 



deeply notched, its extremities triangular, SEGMENT OF ABDOMEN. &.UROPOD. 



produced, acuminate; sides of telson deeply 



incurved at base and then broadly convex. Posterior pleopods: acces- 

 sory filament somewhat flattened; rounded at the extremity, about 

 half length of ischium, and arising from a point distant from apex 

 about a third of total length of peduncle. Ischium long and subulate. 

 Peduncle prolonged as a spine external to origin of ischium. Color: 

 deep chocolate brown black, with lighter patches. 



"Locality: Jamaica. 



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

 wants the external antenna; but from the fragments of those that 

 remain, 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." KINAHAN. a 



a Proc. Dublin University, I, 1859, p. 197. 



