476 Miscellaneous. 



(uos. R. 506-508) agree so closely in general characters with the 

 genus Bothriceps, Huxley, presumably from the Hawkesbury Beds of 

 Australia, that they may be regarded as indicating a new species of 

 that genus, for which I propose the name Bothriccps ffuxleyi. 



The skull of this species is distinguished from that of the typical 

 B. avstralis by its smaller size and narrower contour, the extreme 

 length being about 2| inches in the specimen which I take as the 

 type (no. R. 507). The sculpture is of the pitted nature charac- 

 teristic of the typical species of Bothrkeps, which at once serves to 

 distinguish this form from Petropliryne, Owen, which (as Prof, von 

 Zittel has pointed out) appears to be inseparable from MicrophoUs, 

 Huxley. 



The occurrence of Bothrkeps in the Australian Hawkesbury Beds 

 and the Karoo System of the Cape district is paralleled bj- that of 

 the Ganoid genus Cl'dhrolepis, which Mr. Smith Woodward has 

 recently recorded from the latter deposits. 



On the Phosphorescent Infection of the Talitri and other Crustaceans. 

 By M. A. GiAED. 



Several naturalists have noted the phenomenon of phosphorescence 

 in Amphipoda of different groups and often badly determined (Gam- 

 marus, Talitruff, Orchestki, &c.). Tilesius, Yiviani, Suriray, and 

 Snellen van Yollenhoveu have cited cases of this kind, and the Eev. 

 T, Stebbing, in the admirable bibliography of his Report upon the 

 *■ Challenger ' Amphipoda, has summarized these older observations. 

 In most cases the observed phosphorescence did not belong to the 

 animal itself. In Talitrus, especially, M. de Quatrefages has indi- 

 cated the cause of this apparent phosphorescence ; it is due to 

 Noctilucce which attach themselves to the carapace of the Amphipod 

 as they lie upon the damp sand after the retreat of the tide*. 

 Therefore my surprise was great when, on the 3rd September last, 

 I found on the beach at Wimereux a phosphorescent Talitrus of 

 such intense and continuous lustre that the Noctilucce evidently had 

 no part in the phenomenon. It was at 10 o'clock at night, and 

 notwithstanding the brightness of the moon, then nearly at the 

 full, the luminous Talitrus could be perceived at a distance of 

 several metres. The light was greenish ; it proceeded from the 

 interior of the body of the Crustacean, which was completely illu- 

 minated to the extremities of the antennte and legs, and presented 

 no dark points except the two eyes, which formed two black spots 

 upon this brilliant ground. The animal walked slowly upon the 

 sand, instead of leaping briskly like its congeners. All search made 

 on the same night and following evenings to find other Talitri in 

 the same state were absolutely unsuccessful. 



This excessive rarity of the phosphorescent Talitri upon a beach 

 on which those animals exist in thousands led me to suppose that 

 we had to do here with a parasitic action rather than a physio- 

 logical peculiarity. Therefore the next day I examined under the 

 microscope a leg cut oif from the luminous animal. This limb 

 proved to be stuffed with Bacteria swarming among the muscles, 

 and particularly visible in the terminal joints, which were thinner 

 and more transparent. Under the influence of this microbe the 



* " Sur la phosphorescence de quelques Invertebres marins," in Ann. 

 Sci. Nat. s6r. 3, vol. .xiv. p. 236, 18.50 (see also ' Sillimaivs Journal,' vols. xv. 

 and xvi., nnd ' Anual*,' ser. 2, vol. xii. pp. 15 and Is0, ISoo). 



