CIRCULATORY APPARATUS OF THE NEMERTEA. 3 
by McInrosH in his splendid Monograph on the group 
(18); I can here be satisfied with referring to, that standard 
work. 
McInrosH himself made a very marked advance in our 
knowledge of the subject here treated, by detecting and clearly 
describing the difference between the vascular apparatus of the 
Hoplo- and of the Schizonemertea, more especially with 
respect to an interesting particularity obtaining in the ceso- 
phageal region of the latter group where a system of 
spacious lacunz surrounds this portion of the intestine, 
merging into the three typical vessels at a point further 
back towards the tail. He, however, erroneously looks upon 
these lacunze as the direct continuation of the median 
blood-vessels. He ascribes a respiratory meaning to this 
lacunar arrangement. 
McIntosu similarly discriminated the differences occurring 
in certain Paleonemertea, where he mentions the two 
spacious lateral vessels of Cephalotrix and Carinella 
being the only portions that constitute the circulatory ap- 
paratus. 
Ray Lanxkester (17) and Husrecur (19, 20, 21) have called 
attention to the presence of hemoglobin in the circulatory 
fluid of Nemertea. It is, however, not improbable that the 
former operated not upon Polia sanguirubra, Quatr., as he 
indicates, but upon Cerebratulus urticans (J. Mill.), 
Hubr. In the latter species it is, however, not the blood but 
the proboscidian fluid that contains hemoglobin, as demon- 
strated by Husrecut. The latter found it impregnating the 
blood-corpuscles of Drepanophorus. | 
In 1875 MclIntosuH (24) describes a communication which 
he says exists between the proboscidian chamber and the 
cavity of the vascular apparatus. This observation has hither- 
to remained unconfirmed, although I have myself tried to test 
it in all the different species I investigated. 
_ This author’s description of the circulatory channels of 
Valencinia Armandi (=Carinoma mihi) (25) is noticed 
further on. In 1876 he figures the curious passage (26) of 
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