40 Mr. C. Forstei-Cooper on 



All the fragments come from the Upper Eocene at Uordwell 

 in the Isle of Wight, and the following list represents, so far 

 r.s I am awaie, all the known specimens. 



In the British Museum : 



1. Palate with complete dentition of both sides. (Type.) 



2. Two portions of upper jaws with molars. 



3. Part of risiht mandibular ramus with pml, mYTJTTi- (Type.) 



4. Part of ri;rht mandibular ramus with pm ~4, m TTaTs, and sockets 



for front teeth. 

 «5. Part of ri<i;ht mandibular ramus with pm4, m 1.2.3. 



In the Sedgwick Museum : 



1. Part of the interorbital region of skull with the hind part of the 



palate and the last two molars of each side. 



2. Middle part of left ramus with pm 2~3.'4, m rT27z- 



3. Middle part of corre.spouding right ramus associated with the 



above pm (Tl, m 1.2.3- 



4. Comp'lete hinder part of left ramus with the three molars. 



6. Various smaller fra.!?ments in poor condition, also separate teeth. 



The position of Microchosnts cannot be satisfactorily deter- 

 mined, owing to tiie unfortunate lack of skeletal parts other 

 than jaws and teeth ; but since the descriptions of this form 

 hitherto published have been brief and the figures not alto- 

 gether satisfactory, it is perhaps worth while to refigure it, in 

 view of it.? possible relationship with the American form 

 Hyopsodus (now regarded as an Insectivore) as well as with 

 Necrolemur and other primitive Primates. 



The upper teeth are nine in number, forming a closed series 

 2*5 cm. in length, showing considerable curvature and having 

 a width of 2 cm. at the widest point (measured at the outside 

 edges of the second molars). The palate shows some signs 

 of having a posterior thickened border *. 



Tiie teetli are as follow s : — In front is a large single-rooted 

 tooth on each side, separated the one from the other by a 

 considerable space in which another small pair of incisors 

 could have been present. This part, however, is broken 

 away. The two large teeth measure 2'5 mm. in length and 

 1*75 in breadth, and probably represent the second pair of 

 incisors. The following tooth is smaller and round, 1"5 mm. 

 in diameter, and must be regarded as the third incisor. In 

 this case the next tooth, which is but little smaller than Ig, 

 represents the canine, although the maxillary suture cannot 



* The Cambridge specimen shows indications of large orbits with 

 narrow frontals in between. 



