456 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



hesitate to describe a species of Tomocerus as new until he has ascer- 

 tained, at least approximately, the range of variation in these dental 

 spines; and that of the claws and body color as well, it niay be added. 



For describing the dental spines 

 Agren ('03, p. 144) used a formula 

 which has been generally adopted. 

 Such a formula for plate 40, figure 



2, would be ^—g. Here the hori- 

 zontal line represents the suture 

 between the proximal and middle 

 series of spines, and the fat-faced 

 type indicates the larger size of 

 certain spines. In this paper I 

 have changed the formula a little 

 by running it on a single line, 

 using an oblique line to indicate 

 the suture. Thus the preceding 

 formula becomes 1/7, 2. 



The form of the mucrones is 

 distinctive of Tomocerus (and Tri- 

 tomurus) if we leave out of conr 

 sideration two apparently aberrant 



European species, namely, doderii Parona and niveus Joseph. Each 



mucro (fig. 10) bears dorsally (the furcula being extended behind the 



body) two large proximal teeth, an 



apical tooth or hook, and a large 



anteapical tooth; and between the 



basal and apical teeth there is, in 



almost all species of the genus, a 



series of small, equal, "intermediate 



teeth," which vary slightly in number in individuals of the same 



Fia. 9.— Tomocerus flavescens, vae. sepa- 

 RATUs. Bases of dentes to show seg- 

 mentation AND spines. X 124. 



Fig. 10.— Tomocebus flavescens, vae. 

 SEPARATUS. Right mucro. X 275. 



Key to Species of Tomocerus. 



Intermediate dental spines subequal or gradually increasing in size distally; two 



large distal spines (plate 40, figs. 2, 4, 6) flavescens, p. 457. 



[ntermediate dental spines unequal, with a large spine near the middle of the series; 

 one large distal spine (plate 40, fig. 8; plate 41, figs. 10, 13, 14). 

 Teeth of unguis 4 to 7: 



Dental spines simple vulgaris, p. 463. 



Dental spines tridentate minor, p. 466. 



Teeth of unguis 2 Udentatus, p. 463. 



