SUMMARY OF CURRENT RESEARCHES. 377 



ventral rudiments. The liver is an elongated single lobe. There is 

 atypical thymus arising from clefts 2, '^, 4, and 5. A thyroid arises as 

 a solid median derivative of the floor of the pharynx. It is elongated 

 and bilobed anteriorly. The spleen develops early, is very conspicuous, 

 and multilobed at first. 



The pronephric chamber and tubule are formed from the nephro- 

 tome of the third trunk myotome. There is no communication at any 

 time between splanchnocoele and nephrocoele of the pronephros. The 

 archinephric duct is formed from the nephrotomes of the segments 

 posterior to the third ; the conversion of these nephrotomes into a 

 duct takes place simultaneously, involving no backward growth of the 

 archinephric duct. The pronephros is still present in the oldest larva 

 examined. Mesonephric tubule rudiments occur from about segment 25 

 to segment 43, each arising as a rounded clump of darkly-stained cells 

 in the immediate neighbourhood of the archinephric duct. This rudi- 

 ment is gradually moulded into a twisted tubule, one end of which 

 becomes converted into a Malpighian capsule of the usual type, the 

 other end acquiring an opening into the archinephric duct. There 

 are no peritoneal funnels. Secondary mesonephric tubules arise in con- 

 nexion with the archinephric duct and with the primary mesonephric 

 tubules. The anterior much-coiled part of the archinephric duct, as 

 well as the mesonephros, is surrounded by pseudo-lymphatic tissue. 



The development of the heart and vascular system agrees generally 

 with that described for other Telosteans. The free anterior part of 

 the left posterior cardinal disappears, the large right posterior cardinal 

 conveying the blood of the inter-renal vein to the heart. There is a 

 close connexion between the blood-vessels of the hinder ends of the 

 kidney and liver, recalling the posterior vena cava of Pohjpterus. The 

 sub-intestinal vein, the front end of which is the vitelline vein of the 

 earlier stages, persists in the adult as an hepatic vein. This hepatic 

 vein joins up with the left anterior cardinal and left jugular to form 

 the left ductus Cuvieri. The right ductus Cuvieri shows no special 

 peculiarity. 



The brain is at first solid and is hollowed out secondarily. Sagittal 

 sections through the brain at different stages show the usual Teleostean 

 characters. The cerebellum is late in developing, and goes on growing 

 after metamorphosis. The optic lobes of the mature brain are rela- 

 tively smaller than in the developing one. The mid-brain of the adult 

 is the least conspicuous part. The mature brain is elongate, as also 

 are the olfactory and optic nerves, the divisions being well separated off. 



Spermatozoa of Gorilla.* — G. Retzius finds that these closely re- 

 semble those of the chimpanzee. They are much nearer the human 

 spermatozoa than those of the chimpanzee are. There is considerable 

 variability in the length of the tail and in the shape and size of the 

 head. The more or less flattened head shows, when seen on its broad 

 surface, an elongated oval form. A cap covers the anterior half, but 

 is sometimes quite small. Seen edgewise, the head is conical, with a 

 broad rounded posterior darker portion, and a pointed clearer anterior 



* Anat. Anzeig., xliii. (1913) pp. 577-82 (11 figs.). 



