622 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
primary part of the laryngeal skeleton — that is the arytenoid, cricoid, 
and tracheal rings — is derived from the fifth branchial arch, and that 
its muscles are derived from those of the same arch. 
Function of Pancreas in Squalid©.* * * § — Prof. E. Yung finds that 
extract of pancreas from Scyllium catulus and Lcnnna cornubica contains 
ferments dissolving starch, emulsifying fats, and digesting fibrin. The 
last enzyme sometimes fails to act ; the conditions of its activity remain 
inadequately known. A little piece of spleen mixed up with the pancreas 
in preparing the extract is an effective condition. 
Optic Nerve in the Sciuridae.t — Dr. Rudolf Krause describes a re- 
markable condition of this nerve in Spermophilus citillus. The nerve is 
compressed in cross section, and on reaching the eye swells out into a 
long oval body closely applied to the surface of the sclerotic. Inter- 
nally, the papilla nerii optici is found to form a band 6—7 mm. long, over 
the whole of which rods and cones are absent. The papilla is richly 
supplied with blood-vessels. A description of the eyes of some other 
Sciuridee is promised. 
Tailless Eatrachiaus of Europe.! — Mr. G. A. Boulenger has com- 
pleted his account of these Amphibians. The present part deals with 
Bufonidas, Hylidae, and Ranidae. The text and the illustrations are 
worthy of each other, and it is impossible to refrain from congratu- 
lations. 
Electric Organ of Malapterurus electricus.§ — Dr. E. Ballowitz has 
recently investigated this organ. In its structure he finds much general 
resemblance to the conditions seen in other electric fish. He expects to 
publish full details later, but confines himself in the present paper to a 
brief description of the peculiarities of the nerve-endings. It has been 
long known that in Malapterurus there is not a complicated network of 
nerves, such as that found on the plates of the electric organ in other 
electric forms, but the exact nature of the nerve-endings has been 
hitherto unknown. The author was extremely successful with pre- 
parations by Golgi’s method, and found that the plates of the organ are 
somewhat disc-shaped, the pcstericr surface of the disc being prolonged 
into a partially hollow and partially solid process called by the author 
the funnel, terminating in a swollen knob. On the surface of this 
knob lie 2—4 spirally coiled nerve-fibres with free varicose ends ; these 
replace the nerve network seen in other forms. 
Electric Organ of Mormyrus.|| — Dr. J. Ogneff has investigated by 
means of modern methods the electric organs of three species of 
Mormyrus. His results in general confirm those of the older observers, 
and emphasise the resemblance between the feebly developed electric 
organs of this fish and the more specialised organs of forms like 
Gymnotus and Torpedo. 
As is well known, in all species there are four electric organs, two 
* Comptes Rendus, cxxvii. (1898) pp. 77-8. 
t Anat. Anzeig.j xv. (189S) pp. 110-11. 
X ‘ The Tailless Batracliians of Europe,’ by G. A. Boulenger, pt. ii. Svo, London, 
1898, printed for the Ray Society, pp. 211-376, pis. xi-xxiv. figs. 78-124. 
§ Anat. Anzeig., xv. (1898) pp. 85-92. 
jj Zeitschr. f. vriss. Zool., lxiv. (1898) pp. 565-95 (1 pi.). 
