562 SUMMARY OF CURRENT RESEARCHES RELATING TO 



to the mouth. The rhythmical mouth movements were found to have a 

 temperature coefficient of about 3 "2. The food in the intestine is in 

 the form of oval masses surrounded by a capsule ; during digestion the 

 food capsules become at first relatively acid, then more alkaline. 



In starfishes (Asterias, Porania) the pyloric cseca become acid to 

 congo-red during digestion. After Pecten is fed on Diatoms the 

 skeletons are found in the style, which is probably formed by the 

 mixing of the food with the secretion of the digestive gland. Various 

 observations were made on the formation of enzymes and on the 

 conditions in which they act. 



Theory of Abyssal Light.* — C. C. Nutting brings forward a 

 number of facts which seem to him to indicate that a "bathyssal" 

 light, produced by phosphorescence, may be sufficient to be of use to 

 deep-sea animals. The eyes of "bathyssal" animals are larger, on the 

 average, than those of their relatives in shallow water. These enlarged 

 eyes are regarded as an indication that the abyssal light is sufficient to 

 be of utility to their possessors. The coloration of deep-sea fishes is 

 largely protective . and aggressive. The coloration of the lower In- 

 vertebrates is thought to be adaptive, as in the case of shallow water 

 animals. The coloration of commensals may be protective. It is held 

 to be possible that the phosphorescence of the lower eyeless forms, such 

 as Ccelentera, may be of the same utility as alluring coloration among 

 the higher animals. 



"O' 



Intensive Study of Plankton around South End of Isle of Man.j 

 W. A. Herdman, A. Scott, and W. J. Dakin have co-operated in an 

 interesting study, some of the general conclusions of which may be 

 stated. There is a great increase in spring, due mainly to the sudden 

 appearance of enormous quantities of Diatoms. There is usually a 

 second less marked and less constant increase in September to October. 

 It is largely composed of Copepods, but some Diatoms, and on occasions 

 Dinoflagellates in quantity may also be present. The Dinoflagellates 

 have usually one well-marked peak or maximum in the year, and that 

 lies somewhere between the extremes of April and August. On the 

 whole, the Copepods have their greatest abundance in early summer 

 (May and June), and again in autumn (September). There is usually 

 a marked drop about midsummer. As a rule the Dinoflagellate maxi- 

 mum in early summer is later than that of the Diatoms, but precedes 

 that of the Copepods. Some organisms, such as nauplii of Balanus, 

 show a remarkable regularity in their time of appearance. The most 

 populous zone in the sea is below the surface, but above 10 fathoms. 

 The memoir includes some interesting photographs of " monotonic " 

 plankton. 



Vestiges of Thyroid in Chlamydoselachus and Dogfish.} — T. 

 Ooodey found in Chlamydoselachus anguinws that a narrow tube, 

 intimately connected with the thyroid gland, extends from the thyroid 

 (a compact mass on the ventral surface of the basihyal cartilage) to the 



* Proc.7th Internat. Zool. Congress, 1907 (advance print published 1910) p. 11. 

 t Lancashire Sea Fisheries Lab., 18th Rep. (1910) pp. 193-297 (21 figs.). 

 % Anat. Anzeig , xxxvi. (1910; pp. 104-8 (4 figs.). 



