39 



THE ANIMAL KINGDOM. 



junction with the latter veins, contractile ' lymph-hearts ' are developed. 

 The Crocodile alone has a lymph gland which is situated in the mesentery. 

 There are no valves to the lymph-vessels. 



The kidneys are usually more or less lobed and placed posteriorly in 

 the body cavity, especially in the Lacertilia, an order in which the two 

 glands are sometimes united at their hinder ends. In serpentiform genera, 

 e. g. Anguis, the right gland is in advance of the left, an arrangement more 

 marked in the Ophidia. The glands are also elongated, and in Ophidia the 

 separation into a series of lobes one behind the other is often carried so far 

 that the lobes become independent, and are connected only by their union 

 with a common ureter. There is a cortical as distinct from a medullary 

 region in the Crocodile. The two ureters open on the dorsal wall of the 

 cloaca. Remains of the Wolffian body (' golden yellow body ') and its duct 

 are to be found in many Lacertilia and Ophidia : they have also been found 

 in Chelonia. The testes and ovaries are bilaterally symmetrical glands, but 

 in Lacertilia the right organ, especially the ovary, is rather larger than the 

 left and is placed slightly in advance of it. The differences of size and in 

 position are greater in Ophidia. In both Lacertilia and Ophidia the glands 

 are placed anteriorly to the kidney. A continual formation of new ovisacs 

 takes place during life. The oviducts have simple apertures : the right is 

 generally longer than the left. The convolutions vary from time to 

 time and are more developed during the breeding season. The vasa 

 deferentia open with the ureters. There are two distinct types of copula- 

 tory organs. The Lacertilia and Ophidia have a pair of eversible sacs 

 opening into the cloaca, and when in repose lying under the skin of the 

 tail. The surface of these sacs is covered with spiny processes. Their 

 homologues are to be found in the female. The Chelonia and Crocodilia 

 have two fibrous cavernous bodies closely united into a penis but traversed 

 by a furrow and situated on the dorsal wall of the cloaca. In the Chelonia 

 and Crocodilia two peritoneal canals or extensions of the coelome enter 

 the penis. They have been observed to open on papillae at the base of 

 the glans in the Chelonia : by pores at the base of the penis (or clitoris) in 

 the Alligator, but in the Crocodile the two papillae in the same position 

 are imperforate (Bridge). These canals are possibly the homologues of the 

 abdominal pores found in Elasmobranchii and other fish. Accessory glands 

 appear to be generally absent. Glands opening into the cloaca have been 

 found in Geckoes (female) and in Lacerta. The albumen of the egg, 

 and the more or less calcareous shell are secreted by the glands of the 

 oviduct. 



Most Reptilia are oviparous. Some are viviparous, e. g. Zootoca vivi- 

 para, the Blindworm (Angtiis fragilis], Seps, Chilian Iguanas, among 

 Lizards : many Chilian snakes, the Viper (Pelias berus\ among Ophidia. 

 Other viperine snakes and even a Boa Constrictor have produced living 



