358 EDWARD S. MORSE ON 



this discovery and, furthermore, stated that the true blood-prop eUing organ was the 

 pyriform vesicle described by Huxley ('56) as appended to the dorsal surface of the 

 stomach, and, until recent years, Hancock's interpretation has been the one usually 

 accepted. Joubin ('92) finds Hancock's description of this vesicle absolutely correct in 

 detail, the disposition of the muscular fibers alone excepted. But what Hancock mistook 

 for arteries, Joubin designates as lymphatic lacunae and he considers the "heart of 

 Hancock" intimately related to the digestive system, in fact an absorbent lymphatic 

 system with a propellent heart which directs the nutrimental fluid derived from the 

 intestine, toward the various organs of the animal. In one figure Joubin shows a series 

 of openings which he believes connects the heart with the alimentary tract. This may be 

 a fair interpretation of the pyriform vesicle if it can be shown to be pulsatile. The 

 accessory " hearts of Hancock " are equally puzzling. Joubin considers these vesicles as 

 accidental and says they are anomalous and inconstant. They certainly vary greatly in 

 their form and appearance, as I shall show farther on, but they are not anomalous. 



An organ fulfilling the functions of a heart as a propellent structure is a rhythmically 

 pulsating organ, whether it be in the shape of a pyriform, or globular vesicle, or tubular 

 in form. In life, it is seen to pulsate; muscle fibers to induce this pulsating behavior are 

 found, and distinct vessels or lacunae to conduct the circulating fluid back and forth are 

 defined. Semper ('62, '64), Lankester ('73), Shipley ('83), Schulgin ('84), Beyer ('86) ,i 

 and others who have studied the Testicardine brachiopods ahve have failed to find 

 these conditions fulfilled by this so-called heart; on the contrary Joubin and Bloch- 

 mann aver that the organ in question is pulsatile. In the Ecardine forms, where the 

 volume of circulation is the greatest and most active, this vesicle has not been foiind. 

 Neither Glottidia, Lingula, nor Discinisca reveals the presence of any vesicular organ on 



iCarl Semper, in a review of a previous account of liis on living Lingula, says, "In spite of the desire to verify by 

 researches on the living animal the statements of Huxley and Hancock which seem to he most exact, I could only con- 

 vince myself of the correctness of my representations formerly published which to be sure, I can improve in unimportant 

 details, but on the whole must remain as found then. In vain have I searched for that which Huxley is pleased to call the 

 heart." 



Lankester says in regard to Terebratula vitrea, "I entirely failed to convince myself that the organ regarded by Mr. 

 Hancock as a heart really has the function of one in T. vitrea. I repeatedly opened fresh specimens with rapidity, in order 

 to witness its contractions, if any, but never saw such contractions ; nor could I find vessels in connection witli it, nor 

 evidence that it had muscular walls. Dr. Krohn, of Bonn, had equally been unable to obtain evidence that this curious little 

 dilatation has the function of a heart." 



Shipley in his studies of Cistella says, "Like other reci'nt observers I have been unable to find anything corresponding 

 to a central circulatory organ, or to the system of arteries and accessory pulsatile organs described by Hancock." 



Schulgin, writing of Cistella says, "The particles of bhiod are kept in circulation by the ciliated epithelium. Argiope 

 [= Cistella] is, therefore, devoid of a heart and of a closed vascular system." 



Joubin, in his study of Crania says, "There is no trace of the existence of a heart or arterial system. All the organs are 

 bathed in the colorless liquid filling the perivisceral cavity." 



Beyer says, in regard to Glottidia pyramidata, "Our own observations have been only confirmatory of the views held by 

 Shipley, Schulgin and Morse, and the most careful search after the central propelling organ over the posterior slope of the 

 stomach invariably proved unsuccessful in every new series of transverse sections which was made." 



