Claasijicudon of the Mongooses . 521 



more mcIuHl zygomata, and the inflation of the anterior 

 chamber oE the bulla, coupled with the large porforatiou 

 close to the tynjpanic bone. 



As in Ichneiimi(tj Muik/os, and others, the forami'n rolundum 

 opens into the alisphenoiij canal, probaljly ft primitive feature. 

 Ihe teeth of the upper jaw are somewhat more sectorial than 

 in Ichneumia, as is shown more particularly by the narrower 

 palatal portions of the two molars. 



Aritla {ty ])cf(i8ciala), with some points of resemblance to 

 MunnoH in its semiplantigrade pcntadaetyle feet, has nevor- 

 tbele.»3 a more generalized dentition. The higiily developed 

 anal sack and absence of groove on the snout are 8i)ecialized 

 features. In one character connected with the skull it differs 

 from all the genera hitherto considered {? Rhynch<>(/ale) — 

 namely, in the opening of the foramen rotundum direct into 

 the temporal fossa and not into the alis|)hcnoid canal, the 

 anterior aperture of the latter being situated alongside that 

 orifice and separated therefrom by a narrow bony partition. 



Crossarchus (type ohscitrus), reseml^ling Ariela in the 

 particular last mentioned, has a less specialized anal sack and 

 a more specialized snout. 



Suricatu (type suricatta) has always been admitted to hold 

 an isolated position amongst tUe mongooses, and the now 

 ascertained differences in the structure of its ear enhance tlie 

 isolation. 



Generically it may be distinguished from the rest of the 

 family by a complex of associated characters, like the general 

 form of the skull, the elongated snout, undivided upper lip, 

 tetradactyle feet, and nsiked tarso-metatarsus. The shape of 

 the skull, with its bowed zygomata and complete and stout 

 postorbital bais, recalls in a measure that ot Cynictis ; but 

 the great difference in the form of the bullae, apart from 

 other features, precludes the idea of near affinity between 

 the two genera. The long snout and undivided upj)er lip, 

 resembling those features in Crossarchus, are likely enough 

 to be purely adaptive resemblances ; but in the skull there 

 is one significant similarity, namely, the situation of the 

 foramen rotundum alongside the anterior orifice of the ali- 

 sphenoid canal and close to the sphenoidal fissure — a character 

 restricted to Ariela, Crossarchus, ? R/ii/ncho<j<ile,aud Suricala, 

 80 far, at all events, as mongooses are concerned. I think it 

 is a tenable hypothesis that Suricata is a highly specialized 

 offshoot of the Ar'iela-\- Crossarchus stock of this fan)ily. In 

 that case, the ear of Suricafa may be regaidoti as secondarily 

 simplified. Nevertheless, a comparison between this ear and 

 that of the Mascarene Galidictine genera tbrcibly suggests 



