416 SUMMARY OF CURRENT RESEARCHES RELATING TO 



was found possiblo to scparato all the component layers from ono 

 another. The internal surface of the reflector was the only part that was 

 not perfectly transparent; it, with transmitted light, glowed with a 

 beautiful luminous-looking rosy-purple colour. When the light was 

 cut off it was yellowish-green. This colour was found to be due to 

 fluorescence, and not to a pigment. 



A comparison of the photosphcria with other luminous organs pre- 

 sents few points of resemblance. All that can be said is that the cells 

 of the cellular layer arc similar in general appearance to the cells of tho 

 luminous layer in Lampyris splendidula, and that some or other of tho 

 cellular elements in the luminous organs of fishes are the active light- 

 producing agents. The cells of Nyetiphanes may be really the active 

 agents in emitting light, and the fluorescent surface of the stratified 

 layer only an accessory adjunct. 



New Commensal Amphipod.* — MM. E. Chevreux and J. de Guernc 

 describe a new amphipod (Cyrtophium chelortophilum), which was found 

 commensal on the marine tortoises (Thalassochelys caretta), living near 

 the Azores. The new species differs from forms already known by the 

 shortness of its antennae ; it resembles C. Iseve in the smoothness of the 

 upper part of its body, but differs by its shorter head. Its mode of 

 life is like that of C. parasiticum, which lives commensally with a large 

 Holothurian in Port Jackson. In previous records of crustaceans 

 living on tortoises there has never been sufficient evidence to show that 

 their presence was not accidental, but in the case of the present species 

 the habit has been noticed by Prince Albert of Monaco in 1885, and by 

 one of the writers in 1887, while in the latter instance seventy-seven 

 specimens were found. 



Apseudes and the Tanaidae.f — Prof. C. Claus has contributed a 

 detailed account of the structure of Apseudes latreillii Edw., both in 

 itself and in relation to the Tanaidse. He emphasizes the relationships 

 which the Anisopodae (Tanaicke and Apseudidae) exhibit, on the one hand 

 with the Cumaceae in the Thoracostraca group, on the other hand with 

 the Isopoda among the Arthrostraca. In expressing the contrast be- 

 tween Thoracostraca and Arthrostraca, the Anisopoda should be recog- 

 nized as an order correlated with the Isopoda. - 



The Trieste species of Apseudes is probably A. latreillii Edw. The 

 British form with the same title (Spence Bates and Westwoocl) is quite 

 different, (a) There is no ventral joint between the first and second 

 thoracic segment ; they are fused. A minimal trace of the ventral 

 myomere remains as a rudiment, though the joint has quite disappeared. 

 (b) The brain most nearly resembles that of Isopods (Sphseroma), and 

 consists of fore-brain, with central ganglia and lateral eye-ganglia, of 

 the somewhat ventral middle portion with one large ganglion and nerves 

 for the first pair of antennae, and of the hind portion extending over the 

 oesophageal ring, and including ganglion and nerves for the second pair 

 of antennae. Besides the anterior and posterior commissure, there is, on 

 the oesophageal ring, a marked transverse commissure, which is in rela- 

 tion with the ganglia of the second pair of antennae. There is a nerve- 

 ring on the upper lip with unpaired ganglia, as in Branchipus and the 

 Phyllopods. The ventral chain consists of a sub-cesophageal portion, 

 with four distinct pairs of ganglia for the mandibles, maxillae, and 



* Comptes RcikIus, cvi. (1888) pp. C25-8. 



t Arbeit. Zoo]. Inst. Univ. Wien, vii. (1887) pp. 139-220 (7 pis.). 



