Ostracoda from the Cliava-wza/-Z of Hitching Herts. 591 



here adopted. The brain in this Dinosaur seems to resemble 

 that of Iguanodon more closely than any other of which 

 figures have been published. 



Some measurements of this specimen are appended : — 



millim. 



Greatest width of cerebral hemispheres 62 



„ height „ „ 46 



„ „ at cerebellar prominence 69 



„ width „ „ 38 



Depth of pitmtary body from base of infundibiilum . . 31 



Width between roots of trigeminal 36 



Width of medulla at vagus root 30 



Height „ „ „ 38 



EXPLANATION OF PLATE XVI. 



Brain of Ljuanodon, % natural size : 



1. From above. 



2. From side. 



3. From below. 



car., point of eutry of the internal carotids into the pituitary fossa ; 

 c, cerebral hemispheres ; ch., cerebelhmi ; l.l., lateral lobe of cerebellum ; 

 mecl., medulla ; ol., base of olfactory lobes ; op.c, optic chiasma ; pit., 

 pituitary body. 



The Roman numerals refer to the numbers of the cranial nerves. 



LXI. — Ostracoda from the Chara-»ia/-? of Hitchin^ Herts. 

 By Frederick Chapman, A.L.S., F.R.M.S. 



[Plate XV.] 



The Chara-mivA or " freshwater bed " of Hitchin, Herts, is 

 so remarkably rich in Ostracoda that it appears desirable to 

 put upon record more detailed information regarding them 

 than has been attempted up to the present time. 



These Ostracoda of Hitchin have already been referred to 

 in a note by Messrs. Jones and Sherborn, in 1887, on a 

 collection made by W. Hill, Jun., Esq., F.G.S.* The four 

 species there recorded are Cypris incongruensy Ramdohr; 

 IScottia Browniana (Jones) ; Erjjetocypris reptans (Baird) ; 

 and Candona Candida (Miiller). 



The same authors subsequently f note an additional species 

 from the Hitchin beds — Cyjyridopsis vidua (Miiller) ; wliilst 

 for the previously recorded Cypris incongruens they substi- 

 tute Candona jndiescens (Koch) \. 



* Geol. Mag. dec. iii. vol. iv. p. 469. 



t Suppl. Monogr. Tert. Entom. (Pal. Soc.) 1889, p. 10. 



X Op. cit. p. 12. 



