INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 259 



examined, they will be found to be coloured brightly red, to contract 

 rhythmically, and to lose their colour at each contraction ; the cause 

 of this coloration -was the presence of a system of vessels containing 

 a red liquid. When more carefully examined and subjected to a 

 higher magnification, it was found that under the integument of these 

 organs there was a wide-spaced network, and immediately below this 

 there were the vessels ; these latter have thin, but distinct, walls, in 

 which here and there a fusiform nucleus can be distinguished ; the 

 liquid contents of the vessels are, in thin layers, coloured reddish 

 yellow, and when seen in mass, bright red. In the " perivascular 

 spaces" there is a colourless liquid which contains amoeboid cells and 

 granular bodies of various sizes. Both these liquids are expelled 

 when the organs contract, and the movement is so rapid that it is 

 impossible to detect how it is accomplished. As the organs recover 

 their former size, the lacunar fluid is the first to return. We have, 

 then, in these Crustacea, just as in most Annelids, a lacunar haemal 

 system and a red-blood system ; the difierences between the contents 

 of the two are alone sufficient to show that there is no connection 

 between them. 



In the succeeding year Prof, van Beneden found similar, but more 

 simple, arrangements in Congericola and Clavella ; in the former there 

 are four longitudinal ventral trunks, and the two on either side present 

 numerous transverse anastomoses ; in this creature the only vessels 

 found were relatively very large ; the lumen of their tubes was observed 

 to be, for a brief period, effaced, as if a kind of peristaltic contraction 

 was being effected. The observations made by the author in Brazil, 

 on some undetermined species of Lernanthrojms, appear to confirm 

 M. Heider's results ; in active specimens the foliaceous appendages 

 were observed to contract rhythmically from six to ten times a minute, 

 and the elasticity of the cuticle was seen to aid in restoring the organ 

 to its original condition of extension. Previous, however, to his visit 

 to Brazil, M. van Beneden made the highly important observation 

 that the colouring matter of the vascular fluid was identical with the 

 hajmoglobin of vertebrate animals. 



No similar circulating system is to be observed in any other 

 Arthropod, so that while wo are debarred from regarding the arrange- 

 ment found in Lernanthropus as being derived from tho vascular 

 system of the annulate worms, wo have afforded to us a very inter- 

 esting example of morphological independence, notwithstanding tho 

 marked similarity of histological details and physiological duties. 

 Nor can the red blood of tho annelid bo regarded as tho strict 

 homologue of the blood of the Vertebrata ; it can only be compared to 

 the red blood-corpuscles of tlie latter, inasmuch as it never passes out 

 of the vessels in the way in which the corpuscles of tho Vertebrata do ; 

 M. van Beneden proposes, therefore, tlie following nomenclature ; the 

 whole vascular system of tho annelid should be known as the hcematic 

 system, the fluid of the body-cavity as the plasmatic fluid, while the 

 cavities in which it circulates make up the plasmatic system. Tho 

 presence or absence of this system either in Crustacea or in Annulata 

 is regarded as due merely to diffcroucos in histological differentiation ; 



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