16 DISTRIBUTION OF HEMOGLOBIN AND ALLIED SUBSTANCES 



(2) Diffused in a vascular or ambient liquid: 



(a) In a peculiar vascular system of the chstopodous annelids very generally, 



but with apparently arbitrary exceptions. 

 (6) In the vascular system (which represents a reduced perivisceral cavity) of 



certain leeches, but not of all (Nephelis, Hirudo). 



(c) In the vascular system of certain turbellarians, as an exception Polia. 



(d) In a special vascular tissue (distinct from the general blood system) of a 



marine parasitic crustacean (undescribed) observed by Prof. Edouard 

 van Beneden. 



(e) In the general blood system of the larva of the dipterous insect Chironomus. 



(f) In the general blood system of the pulmonate mollusc PlanorUs. 



(a) In the general blood system of the crustaceans Daphnia and Chirocephalus. 



(3) Diffused in the substance of the muscular tissue: 



(a) In the voluntary muscles generally of Mammalia, and probably of birds, 



and in some muscles of reptiles. 



(b) In the muscles of the dorsal fin of the fish Hippocampus, being generally 



absent from the voluntary muscular tissue of the fish, 

 (r) In the muscular tissue of the heart of Vertebrata generally. 



(d) In the unstriped muscular tissue of the rectum of man, being absent from 



the unstriped muscular tissue of the alimentary canal generally. 



(e) In the muscles of the pharynx and odontophore of gasteropodous molluscs 



(observed in Limnccus, Paludina, Littorina, Patella, Chiton, Aplysia) and 

 of the pharyngeal gizzard of Aplysia, being entirely absent from the rest 

 of the muscular and other tissues and the blood of these molluscs. See 

 as to Planorbis above (2, /) . 



(/) In the muscular tissue of the great pharyngeal tube of Aphrodite aculeata, 

 being absent from the muscular tissue and from the blood in this animal, 

 and absent from the muscular tissue generally in all other annelids as far 

 as yet examined. 



(4) Diffused in the substance of the nervous tissue: 



(a) In the chain of nerve-ganglia of Aphrodite aculeata. 



Since Lankester's researches, the list of invertebrates in which hemo- 

 globin exists has been largely increased. Hubrecht (Niederland. Archiv f. 

 Zoologie, 1876, 11, Heft 3; Maly's Jahresbr. ii. d. Fort. d. Thierchemie, 1876, 

 vi, 92) found by spectroscopic examination hemoglobin in the oval blood 

 corpuscles of Drepanophorus and in the red brain ganglia of nemertean worms 

 which are without colored corpuscles. 



Krukenberg (loc. cit.) found hemoglobin in Planai'bis and Apus. 



Van Beneden (Zoologischer Anzeiger, 1880, in, 55) reports hemo- 

 globin in Planorbis corncus, in sea-water gasteropods, in tunicates, in para- 

 sitical copepods (Lernanthropus and Clavelld), and in an undescribed parasitic 

 crustacean. 



Foettinger (Archiv d. Biologie, 1880, i, 405) discovered hemoglobin 

 in an ophiuridean echinoderm Ophiactus virens. 



Regnard and Blanchard (Compt. rend. soc. biolog., 1883, xcvn, 197) 

 found in the blood of certain phyllopods (Apus productus and Cancriformis, 

 and probably Branchipus), of Cladocera (Daphnia} and Ostracoda (Cypris), 

 that the hemoglobin is dissolved in the plasma. 



Howell (Studies from the Biological Laboratory, Johns Hopkins 

 University, 1884, in, 284) found hemoglobin in the blood of a holothurean 

 echinoderm (Thyonella gemmata). 



