264 SUMMARY OF CURRENT RESEARCHES RELATING TO 



apparently devouring young germ-cells. It is just possible that some of 

 the large phagocytes are parasitic amcebse. 



A striking general fact is the close agreement between the oogenesis 

 in this sponge and that in higher animals, and it may be supposed that 

 all the essential processes of oogenesis already existed in pre-choano 

 flagellate Protozoon ancestors common to sponges and Enterozoa. 



Aphroceras cliarensis at Plymouth.* — Arthur Dendy notes the 

 occurrence of Aphroceras (Leucandra) cliarensis at Wembury Bay near 

 Plymouth. This small calcareous sponge is an addition to the marine 

 fauna of Great Britain, and it is interesting that it should have been 

 recently recorded by Miss Jane Stephens from Clare Island. The 

 individuals are usually solitary and less than an inch in height ; the 

 form varies from slender to globular ; the surface, when viewed under 

 a pocket-lens, showed a glistening appearance due to the presence of 

 gigantic oxea in the dermal cortex. This arrangement resembles species 

 of Ute, but the canal system is typically leuconid. The most remarkable 

 and constant specific character is the presence of enormous sabre-shaped 

 apical rays in the gastral quadriradiates, sometimes reaching a length of 

 0"5 mm. 



Symbiotic Sponges. f — N. Annandale, in dealing with associations 

 of varying degrees of intimacy, describes a number of sponges which 

 occur commonly on living shells of Ostrea and Mytilus in the harbour of 

 Madras or in lagoons of brackish water on the east coast of India. 

 From mussel-shells he obtained Mi/cale segagropila (Johnston) var. 

 militaris nov, M. mytilorum sp. n., M. madraspatana sp. n., and Lisso- 

 deiidoryx halanophilus, all of them encrusting forms. Common as a 

 film on oyster-shells in brackish water and also on leaves is Suberites 

 aquse-didcioris sp. n. In its form and method of growth this sponge 

 approaches Prosuberites Topsent, but the possession of horizontal 

 spicule-fibres distinguishes it. 



Protozoa. 



Periodic Reorganization in Paramecium.^ — Lorande Loss Wood- 

 ruff and Ehoda Erdmann describe an interesting process, which they 

 call endomixis in the life of Paramecium aurelia, a race of which has 

 been kept for over seven years and through more than 4500 generations 

 in a perfectly normal manner. The main facts are the following. 

 1. This infusorian can reproduce indefinitely without conjugation under 

 favourable environmental conditions. The so-called life-cycle does not 

 exist. 2. Minor periodic fluctuations (rhythms) occur in the rate of re- 

 production. 3. The rhythms are the obvious physiological expression of 

 periodic internal phenomena. 4. The internal nuclear phenomena com- 

 prise the formation of a complete new nuclear apparatus of micronuclear 

 origin. This is the endomixis. 5. The essential cytological difference 

 between endomixis and conjugation is the absence of the third division 



* Journ. Mar. Biol. Assoc, x. (1914) pp. 258-9. 



t Records Indian Museum, x. (1914) pp. 149-58 (2 pis.). 



X Journ. Exper. Zool., xvii. (1914) pp. 425-516 (4 pis. and 22 figs.). 



