48 SUMMARY OF CURRENT RESEARCHES RELATING TO 



like ancestors. The "interior bodies" and neurofibrils seem to be 

 structurally continuous. Their functional inter-relationship is therefore 

 probable. The ventral division of the median eye is simply a thickening 

 of the hypodermis of the body, and has retained, in the adult, its 

 original position. The lateral divisions of the eye lose all except a very 

 slight connection with, the hypodermis. The ventral division is in 

 position epithelial ; the lateral divisions are, in effect, sub-epithelial. 

 These relations suggest that the lateral ocelli of Eucalanus are homo- 

 logous with the lens eyes of the Pontellidas. The ventral ocellus in 

 Eucalanus corresponds with the ventral eye of Pontella. 



The organ of Claus is regarded as a bicellular, inverted eye. These 

 organs are located symmetrically in the brain. Each cell of an organ of 

 Claus has a basal plate and interior bodies, as in the median eye. The 

 nerves from the organs of Claus do not pass through the basal plates, 

 but leave the periphery of the cell at a point which is opposite to the 

 basal plate. In comparison with the retinal cells, these are consequently 

 inverted. In position the organs of Claus are sub-epithelial, and since 

 they lie in the brain as well, they are strictly comparable to the inverted 

 pigmented ocelli of certain worms. Through the organs of Clans, and 

 not through the " median eye," relationship with worms may be sought. 

 Heretofore the median eye has generally been regarded as inverted, and 

 on this character likened to the eyes of flat worms, which present that 

 condition. Esterly has shown that the median eye of Eucalanus gives 

 no support to that view. 



Annulata. 



Luminescence of Acholoe astericola.* — F. Falger has investigated 

 this luminous Polynoid that lives on starfishes. The luminous area is 

 in the elytra, on a crescent-shaped marginal dark border which blackens 

 with osmic acid. The elytra may shine for 1G hours after their 

 removal from the worm. An essential condition of the luminescence 

 is free oxygen ; an oxidation certainly occurs ; and some stimulus 

 (mechanical, chemical, thermal, or electrical) is always necessary. 



Tubes of Chsetopterus.t — Howard E. Enders has made some in- 

 teresting observations on the formation and enlargement of the tubes of 

 Cluvtopterus variopedatus. The tubes are formed from mucus which, 

 hardens into a parchment-like material, moulded by the ventral lip of 

 the buccal funnel. They are at first tunnels, but afterwards have the 

 form of a U. They can be enlarged both in length and diameter. 



Larva of Lanice conchilega.J — G. A. Elrington gives some account 

 of the larva of this Polychret, which Giard regarded as an adult and 

 named Wartelia gonotheca. The so-called brain-cells which Claparede 

 observed, which were regarded as ova by Giard and Nordenskiold, are 

 in reality glandular cells. They form a dorsal gland, the secretion of 

 which is used in forming the transparent tube which the larva inhabits. 



* Biol. Centralbl., xxviii. (1908) pp. G41-9. 



t Proc. Indiana Acad. Sci., 1907 (1908) pp. 128-33 (2 pis.). 



X La Cellule, xxv. (1908) pp. 103-12 (1 pi.) 



