46 



Vagina more or less completely dividing into two separate passages. 

 Young born when of very small size and imperfect development ; never 

 connected by a placenta with the mother, but when born attached by 

 her to the nipple, from which the milk is forced by herself into the 

 mouth of the young. Scrotum in front of penis. 



DIDELPHIA. (II.) 



II. Brain with the superior transverse commissure with no well defined 

 psalterial fibres; and with the septum very much reduced in size. (Flower). 

 Steruum with a peculiar T-shaped bone (the episternum or interclavicle) 

 in advance of the manubrium or presternum. Coracoid extending from 

 the clavicle to the sternum, and only towards maturity anchylosed with 

 the scapula. The oviducts, enlarged below into uterine pouches, but open- 

 ing separately from one another, as in oviparous vertebrates, debouch, 

 not into a distinct vagina, but into a cloacal chamber, common to the 

 urinary and genital products, and to the faeces. Testes abdominal in posi- 

 tion throughout life, and the vasa deferentia open into the cloaca, and not 

 into a distinct urethral passage. Ureters pour the renal secretion, not 

 into the bladder, which is connected with the uj)per extremity of the cloaca, 

 but into the latter cavity itself. Mammary glands with no distinct nip- 

 ples. (Huxley.) 



ORNITHODELPHIA. (III.) 



I. MONODELPHIA 



ORDERS. 



I. Brain with a relatively large cerebrum, behind overlapping much or all 

 of the cerebellum, and in front much or all of the olfactory lobes : corpus 

 callosum (attypically) continued horizontally backwards to or beyond 

 the vertical of the hippocampal sulcus, developing in front a well-defined 

 recurved rostrum. 



SUPER-ORDER EDUCABILIA. 



A. Posterior members and pelvis well developed. Periotic and tympanic 

 bones articulated with the squamosal ; (etypically, free and otherwise 

 modified, e. g. Tapiridac). 



1. Legs almost or entirely exserted outside of the common abdominal 

 integument. First digit (great toe) of hind foot (pes) enlarged, op- 

 posable to the others, (exceptionally resuming parallelism with them.) 

 furnished with a nail. Brain with a well-developed calcarine sulcus, 

 giving rise to a hippocampus minor within the posterior cornu of the 

 ventricle by which the posterior lobe of the cerebrum is traversed. 

 (Flower.) (Incisors four in each jaw ; etypically, two — or all in upper 

 jaw — suppressed. Clavicles completely developed.) 



