272 DR. C. A. MAC MUNN ON MYOH2EMATIN AND THE HISTOHHiMATINS. 
shows similar spectra. In the heart and pharyngeal muscles myohsematin occurs ; in 
the nephridium spectrum 8, Chart I., is seen ; in the ovo-testis a faint band before D 
and a narrow one in green like the first of haemochromogen ; in the albumen gland a 
similar spectrum (spectrum 10, Chart I.); and the vas deferens gave spectrum 11, 
Chart I., resembling that of the foot closely. All specimens of Limax maximus 
L. flavus and L. variegatus presented similar appearances. 
In Avion ater the nephridium showed a spectrum resembling that of myohsematin 
(cf. spectrum 9, Chart I.), while the spectra of its other organs are the same as those in 
Limax. The spectrum of the nephridium is remarkable for its resemblance to tbat of 
the kidney of vertebrates. 
Ilistohcematins of Arthropoda. 
In this sub-kingdom the histohaematins are the same as those already described ; 
they are well marked in the Crustacea, of which Homarus vulgaris, Cancer pagurus, 
Carcinus mamas, Astacus fluviatilis and Pagurus bernhardus have been examined. 
In the hearts of all these I have found myohsematin, which will be referred to further 
on. Among Araclmida I have examined Epeira diadema * Tegenarici civilis and other 
spiders in which myohsematin occurs, but owing to the smallness of their parts the 
occurrence of other histohaematins although very probable is not quite certain. In 
Insecta we meet with myohcematin in abundance, but owing to the thinness of the 
intestine and the small size of the ovaries, malpighian tubes, &c., one cannot be certain 
as to the presence of the histohsematins, There are, however, exceptions to this 
statement, which will be referred to again. 
Astacus fluviatilis. —In this species enterohsematin is found in the bile, as already 
described by me,t myohsematin in the heart, but apparently not in the voluntary 
muscles. 
In the yellow stomach-wall, after washing well with water, the spectrum in some 
cases shows that figured in spectrum 12, Chart I. This is remarkably like that seen in 
the nephridium of Avion and in the kidney of higher animals (vertebrates). In other 
specimens this spectrum is replaced by another in which the narrow band in green is 
like that found in Urastcr, but this, from what has been already shown, is merely a 
modification of the other (spectrum 13). In the green gland (nephridium) of all the 
specimens examined the same spectrum is seen, and is shown in Chart I., spectrum 
14. The branchiae sometimes show a haemochromogen-lLke spectrum (spectrum 15, 
Chart I.). The ovaries only gave a lutein-like spectrum. 
In Homarus vulgaris one finds myohaematin present in the muscle of the heart, 
but apparently absent in the voluntary muscles. The stomach-wall shows a faint 
band before D, and another faint and narrow one in green similar to those seen in the 
* The livers of these spiders show a distinct band before D and a darker one in the green, therefore a 
histohaamatin spectrum; cf. Carcinus. 
| Proc. Roy. Soc., vol. 35, p. 381. 
