472 SUMMARY OF CURRENT RESEARCHES RELATING TO 



frontal. If Xenodon be compared with the least specialized of the 

 vipers, Causus, it will be seen that a slight tilting up of the maxilla 

 of Xenodon, with the loss of the few front teeth and a very slight change 

 in the bone, is needed to bring about a condition similar both in struc- 

 ture and mechanism to that of vipers. The theory of the derivation of 

 vipers from Proteroglyphs must be given up. G. A. Boulenger's view- 

 that they are derived from Opisthoglyphs is confirmed. 



Urostyle and Spinal Cord of Frog.* — Geo. E. Xicholls notes that 

 in young specimens of Ram temporaria the filum terminale of the 

 spinal cord lies uncovered (except for connective tissue) upon the dorsal 

 surface of the urostyle. In the adult R. tigrina he observed that the 

 neural canal in the urostyle turned sharply up and extended quite to the 

 dorsal margin, where it opens into a groove. In this open groove, ex- 

 tending approximately along the middle third of the dorsal surface of 

 the urostylar crest, the end of the filum terminale lies. In some 

 specimens the uncovered extremity of the neural canal is very short. 

 Examination of other species of Rana, and of species of Bufo and Hyla, 

 showed the emergence of the filum terminale. The condition described 

 is probably normal for the Anura generally. 



Diseased and Abnormal Conditions of Marine Fishes.f — James 

 Johnstone refers first to piscine sarcomata, and in particular to multiple 

 tumours in halibut and cod. The halibut was suffering from multiple 

 melanotic sarcomata. These may have arisen by metastatic growth, 

 fragments of an original tumour having been distributed through the 

 lymph channels. But the general appearance rather suggested that 

 the separate sarcomatous nodules had arisen in situ independently of 

 one another, perhaps as the result of infection of some kind. The cod 

 showed a large sarcomatous tumour undergoing profound autolytic 

 degeneration. A multiple sarcoma of the mixed-cell type had grown to 

 impossible dimensions. Deficient vascular supply (for the paucity of 

 blood-vessels in such tumours is notable) had prevented the removal of 

 products of katabolism, and had starved the cells. " Stewing in their 

 own juice," the sarcomatous cells were killed and disintegrated into 

 " mush." Accompanying this process of poisoning of the cells there 

 was probably a process of true autolysis, or self-digestion of cells and 

 capsules by their own enzymes. Products of cell excretion diffusing 

 into the adjacent muscle substance affected the latter injuriously, so 

 that degeneration of the fibres set in. The excretory products entering 

 the blood stream of the fish produced marked emaciation. The end 

 would probably have been the rupture of the tumour and the formation 

 of a huge and fatal abscess. 



Johnstone also describes a " hemangioma " on the left eye of a 

 stickleback (Gasterostens pungitius). It is, perhaps, nearer a varicose 

 vein or a haemorrhoid, and was probably induced by some obstruction 

 in the circulation. Another case dealt with was an ovarian cystadenoma 



• Proc. Zool. Soc, 1915, pp. 239-42 (1 fig.). 



t Rep. Lancashire Sea-Fisheries Laboratory, xxiii. (1915) pp. 18-56 (7 pie. and 



7 figs.). 



