ON THE MEMBRANOUS LABYRINTH OE ECHIISOEHINUS, 4^59 



cyanide of potassium. The conclusion I formed was that for some 

 reason or other, perhaps the greater salinity of the water, the 

 conditions at Burnham were so adverse as to have developed a 

 specially hardy race, which couJd withstand what easily killed 

 those living under more favourable conditions. Nor is this all. 

 When 16 years ago I first began to prepare and mount marine 

 animals in balsam as lantern-slides, and took very little care, I 

 mounted a specimen of iV. diversicolor from the Queenborough. 

 district which shows no trace of decomposition anywhere, and the 

 minute blood-vessels of the parapodia are most unusually well 

 preserved, filled with red blood. I have since preserved or tried 

 to preserve many specimens from the Orwell and the Colne 

 estuary, and, even when using much care, I found that in drying 

 it was very difficult to prevent decomposition setting in from one 

 cause or another, and even in my most successful preparations 

 the blood-vessels are well preserved only here and there. It thus 

 seems that, even when dead, specimens from difi"erent localities 

 may differ much in the power of resisting decomposition ; 

 animals of the same species thus varying in physiological and 

 chemical characters. I may also say that the relative amount of 

 haemoglobin difiiers enormously, some being deep red and others 

 quite pale. 



On the Membranous Labyrinths of UcJiinorJmius, Cestracion, 

 and BTiina. By Charles Stewart, LL.D., E.E.S., E.L.S. 



[Eead 1st March, 1906.] 



(Plate 44.) 



EcHiNORHiNFS spiNOsus. Fam. Spinacidse. (PI. 44. fig. 1.) 



The fish upon which this dissection was made was 227 cm. 

 (7 ft. 6 in.) in length. The utricle showed the usual complete 

 separation into anterior and posterior portions, between which 

 lay the ductus endolymphaticus passing upwards directly to a 

 point immediately beneath the skin, where it passed backwards 

 and enlarged into a pigmented, somewhat rugose distensible 

 chamber, 15 mm. in length and 4 mm. in breadth. From 

 the posterior superior angle of this a minute continuation 

 passed upwards and slightly backwards through the skin to the 

 apertura externa. The anterior utricle and the recessus com- 



