161 



on the right, betweeu the 18^^ and IQtli gill on the left, the 

 renal opening between the IT^li and ISt^l^ gill on the right, between 

 the 16th and iT^li on the left (Fig. 28). The first opening lies between 

 the gills, the second at the inner base of the gill-row. In this respect 

 Chiton (Radsia) chierchiae resembles Acanthopleura ecldnata Barn., 

 Schizochiton incisus Sow. and Lohoplax violaceus Quoy & Gaim. 

 (L. Plate, 49. Bd. 2, 2 Heft, Pag. 403\ 



In Fig. 28 is also seen the neural „Schleimkrause" (L. Platk, 

 49. Bd. 2, 2 Heft, Pag. 417), which is broadened by the renal 

 opening. As to the other »Schleimkrausen". I cannot give any data. 



Of the internal organs I only mention the heart and the radula, 

 because I would not dissect the only specimen. The heart is in- 

 teresting through the presence of 3 atrio-ventricular openings on 

 each side (Fig. 30). So this form resembles Chiton squamosns L., 

 where 3 pair of these openings also occur and Chiton (Radsia) 

 goodalli Brod. with 2 — 4 pair. The position of these openings is 

 quite symmetrical. On the right side these are 5 places of cora- 

 munication between the atria and the surrounding tissues: the 

 first is the sinus arteriosus (Fig. 30 .s. a.), which leads the blood 

 from the branchial veiu to the heart; the other four communicate 

 between the surrounding tissue of the mautle and the right atrium. 

 On the left of these latter only 3 occur. In Chiton {Radsia) goodalli 

 Brod. the heart has, according to Haller 4 pair of atrio-ventricular 

 openings, which however may become asymmetrical, so that there 

 are 4 openings on one side and 3 on the other. Plate however 

 found also 3 openings on the right and 2 on the left (49, Bd. 2, 

 Pag. 68). In my specimen the same thing occurs (Fig. 29). Plate 

 writes: »An dem in Fig. 192 abgebildeten Herzen ist ferner die 

 Zahl der Oeffuungen von Interesse, durch welche jede Vorkammer 

 mit dem umgebenden Mautelgewebe oder durch die vordeste mit 

 der Kiemenarterie communicirt. Es fanden sich jederseits 3 con- 

 stante Pori und ferner links 1, rechts 3 inconstante" (49, Bd. 2, 

 Heft 1, Pag. 68). Here we find on each side the opening of the sinus 

 arteriosus and 4 openings, through which the surrounding tissue 

 is in communication with the atria. The renal opening of this 



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