176 SUMMARY OF CUERENT RESEARCHES RELATING TO 



same individual may vary dorsally from dark-brown, reddish-brown, 

 various shades of yellow, to a very pale greyish-white. When startled 

 the majority become of a bright lemon yellow. One specimen was dark 

 brown in its anterior half and greyish-white in its posterior half ; another 

 was brown on the right half of its body, greyish-white on the left. Cross 

 bars may also occur. In the daytime at the Zoological Gardens it usually 

 kept quiet, sticking to leaves in the terrarium. Though only ii mm. long 

 at the most, it can make leaps of quite six feet. 



Respiratory Movements in Teleosts.*— 0. Holmqvist has studied 

 the mechanism of lowering the mandible, which has no direct retractor. 

 The protractor of the hyoid (the geniohyoid of authors) is not actively 

 used in opening the mouth. It is active in the adduction and protraction 

 of the hyoid arch, and is wholly an expiratory or swallowing muscle. 

 Expiration in Teleosts is a deglutition ; the taking of food into the 

 mouth is associated with inspiration. The insertion of the protractor 

 hyoidei on the lower jaw is secondary ; it is in the interests of the hyoid 

 arch and the protraction of the tongue. It is characteristic of the 

 Teleosts that the coraco- or branchio-mandibular (retracting the lower 

 jaw) should give place entirely to the protractor hyoidei. The lowering 

 of the lower jaw is conditioned by the retraction of the hyoid arch and 

 the raising of the operculum. The ligamentum mandibulo-operculare 

 plays an important part, but there is an intricate automatic mechanism. 

 The muscles concerned in the inspiration-phase conduce indirectly, as 

 it were in spite of themselves, to lowering the lower jaw, but the re- 

 traction of the hyoid arch is the dominating fact. The whole system is 

 an unsurpassed illustration of the greatest efficiency at least cost. 



Reproductive Organs of Fishes. f — H, Chas. Williamson describes 

 the reproductive organs of several fishes — of Spams centrodontus De- 

 laroche and S. cantharus L., which are both hermaphrodite ; of Sehastes 

 marinus (L.), in which the larvas develop in the ovary ; and S. dactylop- 

 terus (Delaroche), which seems to be oviparous. He gives much infor- 

 mation in regard to the anatomical relations of the gonads, their growth, 

 the ova, and the fishes themselves. 



Light Reactions of Luminous Animals. | — E. J. Lund finds that 

 luminescent Lampyrida; and Elateridte, nocturnal in habit, cease to emit 

 light when brought from a dark into a lighted environment. The 

 opposite is also true. It was also noticed that " during strongly 

 moonlit nights the number of individuals as well as the number of species 

 seen were few, compared with the number which appeared during dark 

 nights." 



During nocturnal activity some luminescent animals show a marked 

 reaction to some definite source of illumination. This is well seen in 

 some Syllids and Terebellids, and in a luminous Ostracod. It is 

 not seen in species of Laynpyris ; it is very marked in Pyrophoriis 

 2)Iagiophthalmus, which is attracted from a distance of fifty yards or more. 



* Lunds Univ. Arsskrift, vi. (1910) No. 6, pp. 1-26 (1 pi. and 4 figs.). 



t Sec. Invest. Fisheries Scotland, 1910 (Sept. 1911) No. 1 pp. 1-35 (5 pis.). 



+ Johns Hopkins Univ. Circ. (1911) No. 2, pp. 10-13. 



