DR. C. A. MAC MUNN ON MYOH2EMATIN AND THE HISTOHyEMATINS. 285 
Myohcematin in Mollusca. 
It occurs in all the pulraonates examined. Thus in Li max fiavus the heart muscle 
shows it well; it is present more abundantly in the ventricle than in the auricle. It 
is present in the pharyngeal muscle of the same species (spectrum 2, 3, Chart IV.). 
In Avion ater it is present both in the cardiac and pharyngeal muscle (spectrum 4, 
Chart IV.). 
Limax maximus presents a beautiful myohsematin spectrum in the ventricle of the 
heart, also in the pharyngeal muscle. In the heart and buccal muscles of Helix 
aspersa the myohsematin bands are well marked (spectrum 5, Chart IV.). In the 
microspectroscope, as the drawings show, the bands are coincident with those of 
the myohsematin of other species ; owing to the smallness of the heart I could not 
measure these bands in wave-lengths, but there is no doubt that the measurements are 
the same. It also occurs in the heart and pharyngeal muscles of Helix pomatia. 
Myohcematin in Vertebrates A 
The myohsematin of vertebrates differs in no essential respect from that of inver¬ 
tebrates. In some cases the band before D is slightly narrower, or may sometimes 
(exceptionally) be double. The dominant bands are always the same. 
Fishes. 
In the mackerel (Scomber scombrus) myohsematin occurs in the heart ; it is well 
marked in the ventricle. In the pale dorsal muscles its presence is uncertain, in those 
along the lateral line, whose colour is brownish-red, it occurs mixed with some oxy- 
hsemoglobin ; in other parts of the lateral muscle it is well marked. (Chart IV., 
spectrum 6.) 
In the herring (Clupea heringus) it is found in the ventricle (mixed with oxy¬ 
hsemoglobin as in the mackerel). Its first band being somewhat narrower than usual; 
also in the auricle. It is mixed with oxyhsemoglobin in the more reddish parts of 
the dorsal muscles, and in the pale abdominal muscles it presence is uncertain. 
In the roach (Leuciscus rutilus ) it occurs in the ventricle of the heart mixed with 
oxyhsemoglobin, also in the muscle close to the lateral line; in the paler dorsal muscles 
its presence is uncertain, as is that of oxyhsemoglobin. 
In the tench (Tinea vulgaris) it also occurs in the ventricle of heart mixed with 
oxyhsemoglobin. The dorsal (pale) muscle showed only traces of oxyhsemoglobin, the 
redder muscle along lateral line showed the same with traces of myohsematin. In the 
tongue muscle only oxyhsemoglobin could be detected. 
It has also been found in the heart muscle of the plaice, eel, codfish , salmon, whiting, 
goldfish, and others. 
* I have not thought it necessary to map the bands from tlie voluntary muscles as they are tbe same as 
in the Heart of each animal examined. 
