2 8 



considerably smaller number than observed in Neomenia. They are of various sizes; from smaller 

 single folds to larger ramified ones. 'They are filled with blood-corpuscles, which are either 

 round or oval-shaped and very large with oval nuclei and yellowish cytoplasma. Around the gills 

 there is a compact, dense tissue, which Wirën designates in Neomenia carinata with the name of 

 blood-gland. Lacunae are observed in it, permitting the blood to flow from the adjacent tissue 

 into the gill-lamellae. Around the blood-gland no special blood-sinuses are to be demonstrated ; the 

 blood circulates through the loose connective tissue. In fig. 131 — 133 the red lines ƒ represent 

 the course of the blood and not the presence of a special circular blood-sinus. The blood, 

 flowing trom the gills through the blood-gland and the connective tissue accumulates in some 

 sinuses, dorsally to the cloaca (fig. 132 — 135), by which it is directly led into the atrium. 

 This atrium has originated from the union of 2 invaginations of the distal pericardial offsets, 

 and has therefore a doublé origin ; the ventricle is an invagination of the dorsal pericardial 

 wall (fig. 137). Probably there are also 2 atrio-ventricular openings. Of the blood-sinuses the 

 dorsal and ventral one are to be mentioned, the large nerve knots and the rectum being also 

 surrounded by blood-lacunae (figs. 123, 136, 137). In Neomenia carinata and Dalyelli the atrium — 

 (it is better to say atrium than gill-vein) — is single (Wirën, 6 b , pag. 56), though Wirén believes 

 it to be the coalescence of 2 parts as also appears from his figure 5, plate VIII and from 

 fig. 7, plate IX. In Neomenia grandis the atrium is single. 



The genital glands do not present anything noteworthy. The animals are fully mature ; 

 eggs and spermatozoa occur in great numbers. The part of the cloaca-ducts passing out of the 

 pericardium, is a straight tube with folded wall, built up of ciliated epithelium, surrounded by 

 a strong circular muscle (fig. 138). This part is connected with a spacious bag, with non-ciliated 

 wall and similarly encircled by a muscular layer (fig. 140 vs-\-d). These pouches (fig. 139^. s.) 

 are entirely filled with spermatozoa, the heads of all of them being directed towards the wall. 

 They probably are vesiculae seminales and may be compared to the ampullae of Neomenia 

 grandis (Thiele 8, pag. 240), the latter however being of the nature of widenings of the 

 cloaca-ducts in Neomenia carinata (Wirén 6 1 ', plate VII, fig. 2 B). The cloaca-ducts first proceed 

 proximally in the shape of wide tubes filled with spermatozoa, to bend afterwards and to run 

 distally. At the point of bending a thin winding tube is found, i to the right and 1 to the 

 left, leading into a large receptaculum seminis, a spacious bag of cubical epithelium and filled 

 with spermatozoa (fig. 143). 



The precloacal organ is large (fig. 138). A copulation-organ is entirely absent as is the 

 case in Neomenia Dalyelli. The precloacal organ is of the usual structure, only the end, opening 

 into the cloaca, has a wall composed of cubical ciliated epithelium. The genital products passing 

 from the precloacal organ into the cloaca (ó) are not directly ejected but are also met with 

 in part a of the cloaca (fig. 133 o v). 



The portion of the cloaca-ducts taking its course distally, is provideel with an appendage, 

 not present in Neomenia. To make this clear I must first mention the penis-spicula ("strang- 

 förmige Organe" Wirén; "cordlike organs" Tullberg-, "penis-spicula" Thiele). Their course is 

 shown in figs. 133 — 140. Here too, they consist of a "ïinnenförmige" and "pfriemförmige" bar, 

 running parallel to each other. The penis-spicula protrude into the cloaca, where both bars 



