Johnston on Eschar a. 175 



and flight of the delicate- winged and easily-injured body of the 

 Aphis. I have been informed, that the electric forces at the 

 time were in a most anomalous state, the telegraphs on the 

 railroad refusing at one time to emit a spark or convey intelli- 

 gence, and at another acting with great intensity. 



Description of Aphis. — Antennse with the three basal joints 

 black, the setaceous part dark dirty-green. Head and thorax 

 black ; abdomen in most of them dirty-ochreous, yellow spotted, 

 and varied more or less with black. Nectaria a little longer 

 than the abdomen, dark. Legs, the thighs dark at the top, 

 tibise light greenish-yellow, the feet dark. Wings clear, trans- 

 parent, with the nervures pale dirty-green. 



Description of a specimen of Eschara cervicornis, from Embleton 

 Bay. By Dr. Johnston. 



Coral calcareous, dirty-white when dead, buff-orange when 

 recent, rooted by a calcareous basis, frondose, expanding late- 

 rally, very much and irregularly divided, the divisions flat, 

 kneed, occasionally anastomosing, irregularly or dichotomously 

 subdivided, with the ends often bifid and slightly dilated, the 

 margin smooth, uneven. The apertures of the cells open on 

 both sides, and are arranged in lines, but in the older portions 

 of the coral this linear arrangement becomes obscurely marked. 

 The apertures are quite visible to the naked eye ; and the space 

 between them is porous, but the pores are punctiform and not 

 to be seen without a magnifier. The cells lie in a double layer, 

 and are separated by a wall or lamina behind. In newly-formed 

 portions of the coral they are slightly raised and rounded towards 

 the aperture, which is roundish, with a thin margin and a sinus 

 on its proximal side overlooked by a small denticle. But in the 

 old coral the cells are irrecognizable and entirely immersed, the 

 apertures circular, with a compact smooth depressed rim, which 

 is entire and level with the surface. The old parts of the coral 

 become also thickened by a deposition of new cells on the sur- 

 face ; these are raised or mammiform, and many of them have 

 no aperture developed. 



This description is derived from a specimen procured by Mr. 

 Embleton, in Embleton Bay, and exhibited to the Club at the 

 meeting on the 21st June. The specimen is three inches in its 

 lateral expansion, and one inch in height : the breadth of a divi- 

 sion varies from T ] n th to T 2 oths ; and its thickness from less than 

 a line to about two lines. A small specimen of Cellepora ramu- 

 losa grew in its interstices ; and about the base there was a very 

 perfect specimen of Lepralia variolosa. 



