30 SUMMARY OF CURRENT RESEARCHES RELATING TO 



habits are illustrated. Thus " as the animal became more carnivorous 

 in its diet, capturing larger animals, the condyles became larger and 

 stronger, extended forward, became approximated, and finally fused, 

 forming a type with a large condylar area." All the orders of mammals 

 are passed under review, and their condyles interpreted. 



Hybrid Hares.* — Einar Lonnberg gives scientific evidence of hybrids 

 between the native variable hare of Scandinavia {Lepus timidm Ij.) and 

 the common hare of Middle Europe (-£. europceus Pall.). One specimen 

 showed characteristics of both species, but was physically stronger in 

 certain respects than either of them. Another, with more of the 

 characters of L. europmus than the former specimen, is perhaps a product 

 of a secondary crossing between a hybrid of the first degree and L. 

 eiiropcBus. In two others the characters derived from the variable hare 

 are more dominating, which is again suggestive of a secondary crossing. 



Action of Pituitary Extract upon the Kidney, f — E. A. Schafer 

 and P. T. Herring liave shown that intravenous injections of saline 

 extract of the infundil)ular part of the pituitary body produce dilatation 

 of kidney vessels accompanied by increased flow of urine. It is con- 

 cluded that the infundibular part of this gland produces an internal 

 secretion which passes into the blood, and which, both indirectly owing 

 to its general action upon the vascular system and directly by its special 

 action on the renal vessels and renal epithelium, assists in promoting 

 and regulating the secretion of urine. In short, the internal secretion 

 is ancillary to the renal functions. 



Sympathetic Nervous System in Monotremes.:}: — A. J. P. v. d. Broek 

 describes this in Echidna acideata and Ornithorhy iichns parcuioxus. The 

 sympathetic system of the two types is similar in many respects — in 

 structure and ramification ; in other respects they show important 

 differences from placental mammals. It appears that Ornithorhynchiis 

 approaches a little nearer to the conditions in placental mammals in so 

 far as there is a small ganglion cervicale supremum which is missing in 

 Echidna, and the sympathetic cord does not enter directly into the 

 suprarenal body as is the case in Echidna. 



Squamosal Bone in Tetrapodous Vertebrata.§ — F. W. Thyng has 

 followed this bone throughout the higher Vertebrata. The mammalian 

 squamosal is a membrane bone overlying the otic capsule, and at first 

 intimately connected with the incus (quadrate) by a dense and fibrous 

 stroma. Juxtaposition with the parietal has been secondarily acquired. 

 The supratemporal of Stegocephala has been lost, and its place has 

 been bridged secondarily by the upward development of the squamosal. 

 In the temporal region of the Stegocephalian skull there are two bones 

 external to the parietal. The more lateral (from its relation to the 

 quadrate, otic capsule, and jugal) is the squamosal. The more median 

 is the supratemporal. The term " paraquadrate," introduced by Graupp, 



* Proc. Zool. Soc. London, 1905, pp. 278-87 (2 figs.). 



t Proc. Roy. Soc. London, Series B, Ixxvii., No. B 521 (1906) pp. 571-2. 



X Proc. Section of Sciences k. Akad. Amsterdam, viii. (1906) pp. 91-5 (1 pi.). 



§ Proc. Boston Soc. Nat. Hist., xxxii. (1906) pp. 387-425 (4 pis.). 



