122 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 69 



San Miguel Island ; Allen and Chapman * are authorities for the 

 following observations on Procchimys trinitatis of Trinidad : 



" Three of the adults were entirely tailless, the loss of the tail 

 having evidently occurred in early life, leaving only a broad cicatrix 



where the tail joined the body The tendency in these animals 



to lose the tails renders an examination of the posterior portion of 

 the vertebral column of the tailless examples a matter of interest. 

 Fortunately this portion of the skeleton of two of the tailless speci- 

 mens was preserved, and shows that the amputation occurs at the 

 second vertebra behind the posterior border of the pelvis or just 

 behind the fifth caudal. The four first caudals are normal in size and 

 proportions, and appear to be in a healthy condition ; the fifth caudal 

 is abnormal, the posterior third or half having apparently been lost 

 by absorption. A further interesting fact was noted in skinning the 

 specimens in which the tail was still intact, namely, its easy separa- 

 tion at the fifth caudal vertebra, in several specimens the tail breaking 



at this point in the process of skinning There are popularly 



supposed to be two species, one with and the other without a tail." 



The present impaired condition near the base of the tail, and the 

 absence of any evidence that tailless individuals fail to thrive, sug- 

 gests that a progressive weakening of the part may ultimately pro- 

 duce a normally tailless group of animals. 



At Boca de Cupe these spiny rats are eaten to some extent by the 

 native population. The native name is " Macangue." 



Specimens examined : Boca de Cupe, 7 2 ; Boqueron, 14 s ; Bugaba, 

 19 4 ; Cana, 7 ; Cituro, 4 8 ; Divala, 1 1 4 ; Empire, 2 ; Gatun, 21 8 ; Maxon 

 Ranch (Rio Trinidad), 3*; Real de Santa Maria, 8 s ; Rio Indio 

 (near Gatun), 1 ; Tabernilla, 1 ; Tacarcuna, 3*; Tapalisa, 3.* 



PROECHIMYS SEMISPINOSUS BURRUS Bangs 



San Miguel Island Spiny Rat 

 Procchimys barrus Bangs, Amer. Nat., Vol. 35, p. 640, August, 1901. Type 

 from San Miguel Island, Panama. 



A richly colored insular representative of the widely ranging 

 P. semispinosus group of spiny rats inhabits San Miguel Island, in 

 the Bay of Panama. It differs from the neighboring mainland form, 

 P. s. panamensis, mainly in somewhat richer reddish color. Mr. 



1 Bull. Amer. Mus. Nat. Hist., Vol. 5, pp. 225-227, 1893. 



2 Three in Amer. Mus. Nat. Hist. 



3 Collection Amer. Mus. Nat. Hist. 



4 Collection Mus. Comp. Zool. 



