.■{(Ml rAlil') SKOC.SltKHti 



EntonuK'OHcliua M'CoN . Inriii a siKrial t'ainily. Eutomoconcliulae, li\ llic sitlc dl llir I'aiiiilics 

 i'l/ftridinidae and .X'onclioi'OMdae'^ within the section Myodocopa. («. S. Bkahn and A. .M. 

 X(.)l{.\l.\N, in their work of ISHli. ]i. CriS. write of this ifonus that it ,,|)rol)ably will he J'ouiid lo 

 hehmg to the group Mi/odocapd". \\ lien in 1UU2 a. p. KS8 (i. 8. JiHAUV established the genus 

 CiHionocera lie wrote the genus Heterodesmus as a synonym: ,,? Heterodesmun liKADV." Since 

 tlien — it' we are to judge fn)ni the literature — this form has never been found again, nor have 

 any new species been described that can be referred with certainty to this genus. 



On account of the incompleteness of the description (!. W. ;\ir 1.1.1:1;. when revising the 

 Ostracod group, did not think it ]K>ssible to place this genus systematicalK-. in his synoptic 

 work of 11)12, p. 398 he puts it under the heading of ,,U s t r a c o d u m genera e t species 

 i n c e r t a e s e d i s"; in doing so he wished to point out that it is even impossible to decide 

 which main group within the Ostracoda this genus belongs to. Othei- authors who deal with 

 this group do not touch upon this genus. 



Even from the shape of the shell — the strongly ventricose ventral margin ami thc^ 

 presence of a rostral incisur (the latter is, however, only very indistinctly indicated in the figure 

 and is not mentioned in the text) — it seems very probable that the genus Heterudentnua is to be 

 placed within the group Myudocopa, as G. S. Brady has already done. The fact that the species 

 in question was caught swimming freely in the sea, ,, taken in the towing-net", also supports 

 this supposition. It also seems to me very probable that this genus is closely connected 

 with the sub-genus Siplionoslra established by me above. This is supported, above all, by the 

 fact that, to judge from figs. 6 a, g and h, H. Adamsi has a shell that is developed postero- 

 dorsally into a siphon (presumably) of quite the same type as that of the last-mentioned 

 sub-genus. The hinge of the shell points to the same conclusion. The question as to whether 

 the two forms are distinguished from each other generically oi' not can, of course, not yet be 

 decided, though it does not seem impossible that at some future time it will appear that they 

 ought to be included in the same sub-genus. 



With regard to G. S. BliADv's assumption that Heterodesmus is a synonym of the genus 

 CodoHOcera I may merely point out here that — to judge from the literature — the s^jell of the 

 latter genus is not developed as a siphon posteriorly. 



Siphonostra spin if era n. sp. 



Description: — Female: — 



Shell: — Length, 2,32 mm. Length: height, about 1,8 : 1; length : breadth, about 

 1,75 :1. Seen from the side (fig. 3) it is very elongated with the greatest height at 

 about a third of the distance along the shell; the anterior part is slightly larger than the posterior 

 one. The dorsal and ventral margins are of about the same shape, uniformly arched, the 

 arcuation is moderately strong; they join the anterior and posterior margins without corners. 

 The posterior part of the shell is, at about half the height of the shell, drawn out into a rather 

 •wide process cut abruptly off distally and directed obliquely upwards; the ventral margin of 



