26 



Papillae are entirely absent, which was to be expected, the cuticle being too thin. In 

 this Hemimenia differs greatly from Xeomenia. The layer of hypodermal cells is of unequal 

 height indeed ; sometimes thread-like offsets from the hypodermal cells penetrate into the cuticle, 

 but formation of papillae does not take place everywhere. 



In the small pouches upon the carina the structure differs. There the thickness of the 

 hypodermis is only one cellular layer, whereas the cuticle is thicker than the hypodermis (fig. 122). 

 Sometimes the pouches are more or less divided into two by a longitudinal median fold of the 

 hypodermis (figs. 140 — 141). Here also papillae are absent, but the hypodermal cells have 

 offsets, which pierce the cuticle ; these offsets are either broad or very thin and often provided 

 at the end with a little transparent knob (fig. 122). This might be considered as a papilla, but 

 for its crreat difference from the proper papillae of Neomenia. In the thick cuticle of the 

 pouches the lance-point-shaped spicula are implanted, amongst these thin cuticular columns are 

 situated, usually ending in a little knob. The function of the pouches is not clear, though they 

 have probably to be regarded as a sense-organ. 



The ventral groove is distinct, but very narrow and proceeds to a place close before 

 the cloaca. On either side of the ventral groove a kind of lip is found (cf. Thiele 8, pag. 224). 

 There is some difference between Hemimenia and Neomenia in there being only i ventral fold 

 and not 7 or 9. This ventral fold is large and broad. The epithelium of the ventral groove and 

 ventral fold carries cilia in the posterior portion. The "vordere Bauchdriise" with its transparent 

 very finely fibrillar cells and the "hintere Bauchdriise" are both well developed. 



We should not overlook the organ, described by Thiele as "abdominal spicula", by 

 WiREN as "finger-shaped glands". Fig. 135 shows some openings, round or oval-shaped (a. s.) 

 to the right and left of the ventral fold. The)- are short hollow tubes, lined with cubical epithelium 

 and opening to the e.xterior more distally. It is a moot point whether they are spicula or a 

 trland ; the tubes are entirely or partlj- filled with some cuticular matter. They give the 

 impression of being spicula and not glands. Their number is for the first specimen 6 on each 

 side, for the second on one side 8, and on the other side 10. These numbers are much smaller 

 than those found in Xeomenia. 



A dorso-terminal sense organ, as indicated for Xeomenia grandis, is absent. 



The diaphragma is absent, which was also the case in Neomenia grandis. 



The nervous system fully corresponds to that of Neomenia carinata (Wiri^n 6i) pag. 66, 

 fig. 6 B). The commissures between the ganglion posterius superius and the ganglia posteriora 

 inferiora take a peculiar course; they wind their way between the penis-spicula and cloaca-ducts, 

 ventrally to the intestine (figs. 138 — 140). 



The following is noticed with regard to the structure of the alimentary canal. A longitudinal 

 section through the anterior region of the first specimen is represented in fig. 123, with which 

 correspond the transverse sections of figs. 124 — 130. The mouth-cavity is not spacious; the 

 lateral and dorsal walls are beset with cirrhi ; more or less arranged into bundles and ramified 

 at the base. The "Mundleisten" are in the shape of a hor.se-.shoe. In fig. 124 at (ii is a coecum 

 of the pharynx, directed proximally; at a is a transverse fold of the epithelium. Fig. 125 shows that 

 the coecum d is one continued whole with the mouth- cavity, and represents the two folds of a. 



